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THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 

PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


LESSONS  ON  SHELLS, 


IN  A  PESTALOZZIAN  SCHOOL, 

AT  CHEAM,  SURREY, 


BY   TUB 

AUTHOR  OF  "LESSONS  ON  OBJECTS." 


ILLUSTRATED  BY  TEN  PLATES,  DRAWN  FROM  NATURE. 


THIRD    AMERICAN    EDITION. 


NEW-YORK : 
CHARLES  J.   FOLSOM, 

NO.  40  FULTON,  CORNER  OF  PEARL-STRJEET. 

1842. 


LH05 


O  f 


PREFACE. 


IN  presenting  to  the  public  the  third  American 
Edition  of  this  pleasing  and  popular  little  work,  the 
Publisher  would  only  refer  to  the  success  with 
which  it  has  met  both  in  England  and  in  this  coun- 
try, where  it  has  been  very  generally  adopted  as 
the  best  introduction  to  the  study  of  shells.  The 
author  (C.  Mayo,  Esq.,  of  Surrey,  Eng.)  is  well 
known  for  several  publications  of  a  similar  charac- 
ter, which  have  been  received  with  equal  favor. 
The  following  is  an  extract  from  his  preface  to  the 
present  work. 

Several  circumstances  concur  to  recommend 
conchology  as  the  first  branch  of  Natural  History 
to  be  studied  by  younger  pupils.  Shells  are  of 
themselves  interesting,  from  the  peculiarity  of  their 
forms  and  the  variety  of  their  colours  ;  their  cha- 
racteristics are  simple  and  present  themselves  rea- 
dily to  the  eye,  and  a  variety  of  interesting  infor- 
mation may  be  given  respecting  the  animals  which 
inhabit  them.  Added  to  this,  the  greater  part  of  the 
specimens  may  be  procured  at  little  expense,  may 
be  easily  preserved,  and  therefore  continually  re- 
produced to  the  class,  and  besides  may,  without 
fear  of  damage,  be  committed  to  the  careless  hands 
of  the  youngest  students. 

It  will  however,  I  know,  be  objected  by  stanch 
anti-reformers  in  education,  that  improve  the  mode 
of  teaching  Natural  History  as  you  will,  you  but 

M368636 


iV  PREFACE. 

teach  better  that  which  had  better  not  be  taught 
at  all ;  for  that  whatever  abridges  the  time  given 
to  classical  instruction,  weakens  the  nerves  and 
sinews  of  the  mind,  and  but  debases  the  Corinthian 
column  of  ancient  lore  by  introducing  the  barbarous 
ornaments  of  modern  science.  My  answer  is,  we 
do  not  propose  to  devote  a  large  portion  of  time  to 
Natural  History  in  ordinary  cases,  and  even  ihis 
will  be  taken  principally  during  those  early  years 
when  very  little  real  progress  is  made  in  Greek  or 
Latin.  Every  age  has  its  intellectual  as  well  as 
its  moral  claims,  and  though  the  stern  discipline  of 
early  classical  instruction  may  offer  some  advan- 
tages, still  the  hours  devoted  to  the  abstractions  of 
grammar,  and  the  puzzling  out  ideas  which  have 
no  prototype  in  the  child's  mind  through  the  dark 
mist  of  a  language  little  akin  to  his  maternal 
tongue,  present  very  meagre  food  to  that  under- 
standing they  are  supposed  to  strengthen.  If  the 
child  must  lisp  in  Latin,  let  him  do  so ;  let  his  first 
Gradus  ad  Parnassum  be  through  the  quagmires  at 
its  base ;  the  few  choice  spirits  that  mount  the 
summit  may,  perhaps,  tread  it  with  firmer  step, 
and  enjoy  the  prospect  with  keener  relish;  but  that 
step  will  not  be  the  less  firm,  nor  that  relish  the  less 
keen,  because  a  daily  hour  was  abstracted  for  '  Les- 
sons on  Objects,'  or  c  Lessons  on  Shells.'  Not  only 
are  the  sciences  so  linked  together  that  each  gives 
each  a  double  charm,  but  the  faculties  of  the  mind 
are  so  constituted,  as  that  the  vigour  of  each  is 
promoted  by  the  due  development  of  the  rest.  And 
there  is  a  harmony  as  truly  existing  in  a  properly 
educated  mind,  as  in  a  well  formed  and  well  exer- 
cised body,  though  the  harmony  of  the  former  may 
not  be  so  easily  discerned  as  that  of  the  latter. 

As  years  advance,  the  study  of  Natural  History 
may  be  confined  to  those  who  manifest  a  peculiar 
taste  for  it,  or  who  exhibit  little  disposition  for  clas- 


PREFACE.  V 

sical  pursuits.  For,  as  every  age  has  its  intellect- 
ual claims,  so  also  has  every  grade  of  talent.  The 
schools  of  the  highest  reputation  have  generally 
been  conducted  too  exclusively  to  the  advantage  of 
the  superior  class  of  minds.  The  fine  porcelain  has 
been  beautifully  moulded  and  delicately  pencilled, 
but  the  coarser  clay  has  been  almost  entirely  ne- 
glected. Yet  many  a  young  man  who  will  never 
shine  in  the  Senate  House  or  the  Schools,  may  yet 
pursue  Natural  History  with  success,  and  find  in 
such  pursuits  improvement  for  his  mind,  a  refuge 
from  ennui,  and  a  substitute  for  sensual  pleasures. 
There  is  much  truth  as  well  as  benevolence  in  a  re- 
mark I  once  heard  from  an  amiable  coadjutor  of 
Pestalozzi ;  "  Tout  terrain  est  bon  si  1'on  sait  le 
cultiver." 

Much  of  the  instruction  thus  communicated,  will 
doubtless  fade  from  the  mind ;  but  not  with  it  will 
pass  away  all  the  benefits  arising  from  these  stu- 
dies. In  after  years  they  may  be  recommenced 
with  greater  facility,  in  consequence  of  the  early 
training,  and  every  incidental  reference  to  these 
subjects,  which  conversation  or  literature  may 
present,  will  be  more  readily  seized,  and  more 
clearly  comprehended.  And  may  it  not  be  anti- 
cipated, that  through  the  judicious  introduction  of 
these  branches  of  education  into  our  schools,  the 
latent  powers  of  genius  may  be  kindled,  and  talents 
elicited  that  shall  push  forward  the  limits  of  sci- 
ence,* and  force  the  Proteus  nature  to  reveal  still 
more  of  her  secret  truths  ? 

C.  MAYO. 

*  In  confirmation  of  this  idea,  it  may  be  stated,  that  a  very  in 
genious  improvement  of  the  dissecting  microscope,  which  has 
merited  a  reward  from  the  Society  of  Arts,  has  been  invented 
by  a  very  young  person  brought  up  on  these  principles.  I  have 
the  more  unmixed  pleasure  and  honest  pride  in  mentioning  this 
fact,  as  it  refers  not  to  a  pupil  of  my  own,  but  to  one  educated  at 
Stanmore. 


In  drawing  out c  Lessons  on  Shells,''  the  following  works  have 
been  consulted,  and  extracts  made  from  them. 

Burrows'  Elements  of  Conchology. 

Turton's  Conchological  Dictionary. 

Turton's  Bivalve  Shells  of  the  British  Isles. 

Mawe's  Conchology. 

Montagu's  Testacea  Britannica. 

Fleming's  Philosophy  of  Zoology. 

Lamark's  Histoire  Naturelle  des  animaux  sans 

Vertebres. 

The  Conchologist's  Companion. 
Shaw's  Nature  displayed. 

Sowerby's  Genera  of  Recent  and  Fossil  Shells. 
Dillwyn's    Descriptive    Catalogue    of   Recent 

Shells. 

The  plates  which  illustrate  this  work  have  been  drawn  from 
specimens  actually  presented  to  the  class :  they  are  intended 
as  an  assistant  to  the  teacher,  but  not  as  a  substitute  for  the 
shells  themselves  in  the  instruction  of  pupils. 


NOTE. 


The  following  Table  is  prefixed  to  the  present  edition  of 
this  work  in  order  to  meet  the  change  of  nomenclature,  now 
so  generally  adopted,  by  the  substitution  of  the  names  of 
Lamarck  for  those  of  Linnaeus.*  It  has  been  carefully  pre- 
pared by  Mr.  I.  COZZENS,  Librarian  of  the  New  York  Ly- 
ceum of  Natural  History.  The  student  is  requested  to  refer 
to  this  table  in  connexion  with  the  following  pages, 

Linnctan  names.  Lamarckian  names.       Page*  PI.  Fig. 

Gen.   Conus  marmoreus.  • .  .Gen.  Retained . 70  2  1 

Cyprcea  arabica "      , 74  2  2 

"       monata ,,           «      —  2  4 

"       europea .........           " 74  2  5 

Bullalignaria... "      77  2  6 

"   fontinalis Physa  fontinalis 78  2  9 

!"  volva Ovulavolva ..,«.—  2  8 

Volutaoliva.. Oliva tricolor 81  2  10 

'  .fr  pyrum' Turbinella  pyrum 82  —  •—  . 

"     episcopalis  .......  Mitra  episcopalis.......  81  2  11 

"     musica.. .........    Retained 82  —  •— 

Buccinum;dolium Dolium  maculatum 84  3  1 

harpa Harpa  ventricosa.. 87  3  2 

flammcum....    Cassis flammea — -  3  3 

"       r   undatum......    Retained 88  —  — 

'    lapfflus... Purpuralapillus........  88  —  — 

subulatum Terebra  subulata 90  3  4 

.  »  Lamarck's  system  baa  been  adopted  by  Cuvier,  and  all  distinguished  Naturalists/ 
since  his  tilfle, 


Vlll  NOTE. 

Linncean  names.  '  Lamarckian  names.       Page.  PI t  Fig. 

Gen.   Strombuspes-pelicani.Gen.Rostellariapes-pelicani  92  3  6. 

"                   "    yoking.  "    young  "36 

"          chiragra P  terocera  chirargra ....  93  —  — 

Murex  ramosus Retained 95  4  1 

"     rana... Ranella  crumena —  42 

"     colus Fususlongissimus —  1  — 

"     maculosus........    Triton  maculosum —  4  3 

"     tribulus Murex  Crassispinus. . . .  98  —  — 

"    tritonis Triton  variegatum 98  —  — 

Trochus  ziziphinus Retained —  4  4 

"        dolabratus Pyramidella  dolabrata..  — •  4  6 

"        conchyliophorus  Trochus  agglutinans. . . .  101  ~  — 

u        perspectives.....  Solarium perspectivum..  101  4  5 

Turbo  littoreus..... Retained 104  —  — 

"     scalaris Scalaria  pretiosa 105  4  7 

"     clathrus "     communis 105  4  8 

Helix  pomatia , Retained 109  5  1 

"    hortensis "      110  —  •— 

"    janthina... Janthina  communis.... Ill  —  — 

"    obscura Bulimushordeaceus.,.,112  —  — 

**    cornea Planorbis  cornea —  5  2 

"    stagnalis Lymnea stagnalis —  5^  3 

Neritapeloronta..........    Retained .........114  5  4 

"    corona . Neritina  corona ?.......  114  5  5 

"    littoralis "      littoralis 115  —  — 

Haliotistuberculata.......    Retained 117  5  6 

Patella  equestris Calyptrsea  equestris....H9  5  7 

"     nodosa...... ......    Fissurella  nodosa —  5  8 

"     grseca "         grseca' 122  —  — 

"     pellucida. Ancylus  lacustris. 123  —  — 

"     ungarica. .........    Pileopsis  ungarica 123  6  1 

Dentalium  entalis Retained 125  6  6 

Serpula  lumbricalis Vermetus  lumbricalis  . .  —  6  2 

"      turbularia ;    Retained 127  —  — 


NOTE.  x      IX 

Linnaan  names.  Lamarckian  names.       Page.  PI  Fig. 

Gen.   Serpula  aquaria Gen.  Aspergillum  javanum..!28  6     3 

Nautilus  pompilius Retained 136  6     4 

"        spirula Spirala  peronii 133  1    — 

Argonauta argo Retained.......... —  6     5 

Teredo  navalis...........          " 130  —   — 

Sabella Sabellaria 133  —    —  ; 

Myatruncata Retained ...148.  7     2 

"  margaritifera'........    Unio  elongata 149  —    — 

Solensiliqua Retained 153  7     4 

"    radiatus " 154  7     5 

Tellina carnaria Lucina  carnaria........  157  7^   7 

"     linqua-felis Retained....... ........ 156  7     8 

"     radiata "      156  —    — 

u     madagascariensis..  "      .**.......,....  —  7     9 

Cardiumedule "      ..159  8  1&2 

«         tuberculatum.,.          "      159  — •   — 

Mactrastultorum.. "      161  —   — 

"      compressa "      161  —    — 

Donaxdenticulata.... «      164  8.    6 

Venus  mcrccnaria........           "      ......166  —    — 

"     dysera Cytherea  dysera 167  8.|   8 

Spondylus  gsedaropus. ...    Retained 169  8~    9 

"            plicatula......    Plicatula ramosa 168  8    101 

Chama  hippopus Hippopus  maculatus. . .  .172  9 4    2 

"       cor Isocardia  cor. 171  9     3 

ArcanosB Retained 173j   9j   6 

"  undata Pentunculus  undulatus.,174  9     5 

Ostrea  edulis Retained 177  —    — 

"     malleus.... Malleus vulgaris 178  9     8 

"     maximus.... Pecten maximus  3 

"     violacea "    violacea     bl"" 

Anomia  psittacea Terebratula  psittacea 183  9     9 

"        ephippium Retained 182  10     1 

Mytilus  edulis... « 184  10     2 


X  NOTE. 

Linnasan  names.               LamarcMctn  names.       Page-  PI.  Fig. 

Gen.  My  tilus  margaritiferus, .  Gen.Meleagrina  margaritifera!85  10  3 

Pinna  pectinata Retained 191  10  4 

Chiton  squamosus « 200  10  5 

"      fascicularis „           " 199  —  — 

Lepastintinnabulum Balanustintinnabulum...203  10  6 

«    anatifera... Anatifa  striata ..203  10  7 

Pholas Candida.,,. Retained ,,,....,197  10  8 


EXPLANATION  OF  THE  PLATES 


PLATE  L 


a.  Spire. 

b.  Body  whorK 

c.  Beak, 
f/.  Base. 
e.  Canal. 

/.  Aperture, 

g.  Outer  lip* 

h.  Columellar  lip, 

i.  Whorls. 

k.  Suture, 

.  Apex  j 

m.  Back* 

n.  Yarices* 

o.  Columella. 

p.  Dissepiments, 

q.  Umbilicus. 


r.    Area  or  Anterior 

slope. 
«.     Areola  or  Posterior 

slope 

*.     Beaks, 
u.     Hinge, 
v.     Ligament, 
w.    Disk. 
x.     Umbo, 
y.     Base. 
z.     Length. 
a*    Breadth. 
b*    Auricles, 
c*    Left  valve. 
d*    Right  valves 
«* 


PLATE  II. 


PIG. 

1.  Conus  Mawnoreus. 
2.  Cypraea  Jlrabica 
3.  The  same,  young. 
4.  Cypraea  Moneta 
5.  Cypraea  Europcea    . 
6.  Bulla  Lignaria       • 
'7.  Gizzard  of  Ditto. 
8.  Bulla  Folva        .     . 
9.  Bulla  Fontinalis 
10.  Voluta  Oliva      .      . 
11.  Voluta  Episcopate  . 

.     Marbled  Cone- 
.     Nutmeg  Cowry. 

.     Money  Cowry. 
.     Nun  Cowry. 
.     Wood  Dipper. 

.     Weaver's  Shuttle. 
•  .     Stream  Dipper. 
.     Olive  Volute. 
.     Bishop's  Mitre 

PLATE  III. 


FIG. 

1.  Buccinum  Dolium   .  . 

2.  Buccinum  Harpa    .  . 

3.  Buccinum  Flammeum  , 

4.  Buccinum  Subulatum  , 

5.  Strombus  Pes  Pelicani  « 

6.  The  same,  young. 


Spotted  Tun. 
Harp  Shell. 
Triangular  Helmet 
Tiger  Spire. 
Pelican's  Foot 


PLATE  IV, 


PIG. 

1.  Murex  Ramosus  •    • 

2.  Murex  Rana        .     . 

3.  Murex  Maculosus    . 

4.  Trochus  Zizsiphinus . 

5.  Trochus  Perspective 

6.  Trochus  Dolabratus  . 

7.  Turbo  Scalaris    .      . 

8.  Turba  Clathrus    .      . 


Branched  Murex. 
Frog  Murex. 
Spotted  Murex. 
Livid  Top  Shell. 
Staircase  Shell. 
Zebra  Shell. 
Wentle  Trap. 
False  Wentle  Trap 


PLATE  V. 


PIG. 

1.  Helix  Pomatia.  .       Eatable  Snail. 


2.  Helix  Cornea   . 

3.  Helix  Stagnate 

4.  Nerita  Peloronta 

5.  Nerita  Corona    . 


Horn  Snail. 
Lake  Snail. 
Bleeding  Tooth. 
Coronated  Nerite. 


6.  Haliotis  Tuberculata   .       Common  Sea-ear. 

7.  Patella  Equestris    .     •    {  CLfm^edt.SaUCer 

8.  Patella  JVWoso     .     .      Knotted  Limpet. 


PLATE  VI. 


FIG. 

1.  Patella  Ungarica 

2.  Serpula  Lumbricalis 

3.  Serpula  Aquaria 

4.  Nautilus  Pompilius 

5*  Argonauta  Jlrgo  .     . 
6.  Dentalium  Entalis  . 


Hungarian  Bonnet. 
Cork  Screw  Shell. 
Watering  Pot. 

Large  Chambered 
N|utilug> 

Paper  Nautilus. 
Dog's  Tooth.. 


PLATE]  VII. 


1.  Hinge  of  Mya. 

2.  Mya  Truncata    .     .     Truncated  Gaper. 

3.  Hinge  of  Solen. 

4.  Solen  Siliqua.     .     .     Pod  Razor  Shell 

5.  Solen  Radiatus  .     .     Radiated  Solen. 

6.  Hinge  of  Tellina. 

7.  Tellina  Carnaria     .     Rosy  Tellen. 

8.  Tellina  Lingua  Felis    Cat's  Tongue  Tellen. 

9.  Tellina  Madagascar  \  -*-  ,  ^  „ 

riensis  I  •™-a"agascar  Tellen. 


PLATE  VIII. 


no. 

1.  Hinge  of  Cardium. 

2.  Cardium  Edule 

3.  Hinge  of  Mactra. 

4.  Mactra  Stultorum  . 


5.  Hinge  of  Donax. 

6.  Donax  Denticulata 

7.  Hinge  of  Venus. 

8.  Venus  Dysera  .     .     . 

9.  Spondylus  Gcedaropus 
10.  Spondylus  PUcatula    . 


Common  Cockle 

Simpleton's 
Kneading-trough. 

Toothed  Donax. 

Ribbed  Venus. 
Thorny  Oyster. 
Cat's  Paw. 


^*L  \  w^':  SSI 

•\H'-         •  ''  Vl^r'''     ',\^5s>.i 

^.X-  /  "    •'  ^  -;    '•  il;^- 

^  --  P 


-•9 


PLATE  IX. 


£10. 

I.  Hinge  of  Chama. 

2*  Chama  Hippopus 

3.  Chama  Cor    .     . 

4.  Hinge  of  Area. 

5.  Area  Vndata  .     . 

6.  Area  JYbce      .     . 

7.  Ostrea  Violacea  . 

8.  Ostrea  Malleus  . 

9.  Anomia  Psittacea 


.    Bear's  Paw  Clam. 
.    Heart  Clam. 

•     Lettered  Ark. 
.     Noah's  Ark. 
.     Violet  Scallop. 
.     Hammer  Oyster. 

(  Parrot  Beak 
"  (    Anomia. 


PLATE  X. 


1.  Anomia  Epkippium  .     .     Wnnkled  Anomia 

2.  Mytilus  Edw/ts    •     •     •     Common  Muscle. 

•*-f         f  Pearl-bearing 

3.  MytilusMargantiferus  J    Muscie. 

4.  Pinna  Pectinata  .     .     .     Spiny  Sea  Wing. 

5.  Chiton  Squamosus    .     .     Scaly  Chiton. 

.   ,  (  Bell-shaped 

6.  Lepas  TMinnabulum   .  ^    Baraacie. 

7.  Lepas  Anatifera       .     .     Duck  Barnacle. 

f  White  Stone- 

8.  Pholas  Candida.  •     •     •  \    piercer. 


LESSONS  ON  SHELLS. 


ON  THE  MOLLUSCA. 

LESSON  I. 

Teacher.  Do  you  know  what  these  things  are 
which  I  have  brought  in  as  the  subject  of  our 
lesson  to-day  1 

Child.     They  are  shells. 

Teacher.  Describe  to  me  what  you  mean  by 
a  shell. 

Child.  Oh,  a  shell  is  that  which  covers  a 
snail. 

Teacher.  Yery  true  ;  a  snail  has  a  shell,  but 
in  saying  this  you  do  not  explain  to  me  the  na- 
ture of  a  shell.  When  you  attempt  to  describe 
any  thing,  you  should  give  such  an  account  as 
would  instruct  a  person  altogether  ignorant  on 
the  subject.  Try  again,  and  tell  me  what  a 
shell  is. 

Child.  A  shell  is  a  hard  covering  or  house 
belonging  to  animals  resembling  slugs. 

Teacher.  Of  what  use  do  you  suppose  shells 
to  be? 

Child.  They  must  be  a  defence  and  pro- 
tection to  the  animals  which  they  cover. 

Teacher.  Yes :  shells  are  the  hard  coverings 
of  certain  animals  called  mollusca;  a  name 


10  LESSON    I. 

derived  from  mollis,  the  Latin  for  soft ;  if  you 
call  to  mind  the  animals  enclosed  in  these  cases, 
you  will  not  fail  to  observe  how  applicable  this 
term  is  to  them.  Give  me  some  example  to 
prove  that  this  name  is  well  chosen. 

Child.     The  snail  has  a  very  soft  fleshy  body. 

Teacher.  Yes,  and  the  mollusca  in  this  respect 
are  all  alike.  I  have  brought  you  some  to  exa- 
mine; look  at  them  well,  and  try  and  discover 
the  characteristics  which  distinguish  them  from 
other  animals.  Here  are  a  snail,  an  oyster,  a 
muscle,  a  slug. 

Child.  I  am  sure  that  we  shall  not  be  able  to 
say  much  about  such  animals  as  these,  they  are 
so  shapeless  and  uninteresting  in  their  appear- 
ance. 

Teacher.  Do  not  form  so  hasty  a  judgment. 
I  hope  soon  to  convince  you  that  it  is  your  igno- 
rance alone  which  causes  you  to  view  them  with 
indifference.  There  is  not,  indeed,  any  part  of 
the  creation  which  you  can  study,  that  will  not 
repay  you  for  your  labour  ;  and  when  you  be- 
come better  acquainted  with  the  different  king- 
doms of  nature,  you  will  experience  an  increased 
pleasure  in  your  walks ;  and  objects  that  you  have 
hitherto  passed  heedlessly  by,  will  rivet  your 
attention  by  the  wonders  they  unfold  to  you ; 
but  my  great  desire  is,  that  you  should  trace  in 
all  these  things,  the  hand  of  an  almighty  and 
beneficent  Creator.  When  you  are  struck  with 
the  beautiful  arrangement  in  a  plant,  with  the 
means  of  defence  possessed  by  one  animal,  and 
the  sagacity  displayed  by  another,  consider 


MOLLUSCA.  11 

which  you  ought  most  to  admire,  the  instrument 
or  Him  who  so  well  fitted  and  prepared  the  instru- 
ment for  the  work  to  which  it  is  appointed.  Now, 
suppose  that  you  have  yourself  made  or  done 
any  thing  very  nicely  and  with  great  pains  for  a 
friend,  would  you  feel  satisfied,  or  think  it  just, 
if,  whil'e  your  performance  was  admired,  you 
were  forgotten  f 

Child.  I  should  consider  such  conduct  very 
unfair. 

Teacher.  And  what  lesson  do  you  suppose 
that  I  wish  to  teach  you  by  drawing  your  atten- 
tion to  your  own  feelings  when  your  industry 
and  ingenuity  have  been  thus  overlooked  1 

Child.  That  when  we  are  struck  with  the 
beauty  and  utility  of  any  of  God's  works,  we 
should  praise  him  for  his  wisdom,  and  thank  him 
for  his  goodness. 

Teacher.  It  is  with  such  feelings  that  I  wish 
you  to  study  Natural  History,  and  it  would  then 
prove  a  very  delightful  and  profitable  employ- 
ment.* You  must  now  return  to  the  consider- 
ation of  the  animals  before  you.  Examine  them 

*  It  is  most  important  in  giving  instruction  in  Natural  History, 
early  to  accustom  children  to  recognise  the  God  of  nature  in  his 
works.  If  God  be  robbed  of  his  glory,  how  can  we  anticipate  a 
blessing  on  our  labours  ?  Has  not  experience  proved,  that  the 
study  of  the  wonders  of  creative  wisdom  does  not  lead  the  natural 
heart  to  the  Creator  ?  Is  it  not  notorious,  that  among  the  follow- 
ers of  science  is  continually  seen  the  practical,  if  not  the  avowed 
atheist.  Let  this  be  a  beacon  to  the  Christian  instructor,  aud  let  it 
be  his  careful  endeavour  to  guard  against  the  fatal  error  of  speak- 
ing of  God's  works  independently  of  him.  As  we  are  called  upon 
to  walk  by  faith,  and  not  by  sight,  it  is  essential  to  lead  children  to 
see  God  in  all  things,  and  to  trace  Him  who  is  himself  invisible  in 
those  outward  manifestations  of  his  power  and  goodness,  which  are 
within  the  reach  of  their  observation. 


LESSON   I. 

carefully — exercise  your  different  senses  upon 
them — mark  the  various  parts  of  their  bodies — 
consider  to  what  use  each  part  is  likely  to  be 
destined — and  reflect  upon  what  you  know  of 
their  habits.  By  using  well  your  sense  and  your 
judgment,  you  will  be  able  to  find  out  much  for 
yourselves.  When  you  are  at  the  sea-side,  or 
out  at  sea,  you  may  collect  facts  illustrative  of 
the  history  of  these  animals. 

Child.  That  would  be  exceedingly  interest- 
ing. 

Teacher.  Yes,  it  would  ;  but  you  need  not 
wait  for  such  opportunities.  Rivers,  and  even 
the  garden,  will  afford  you  specimens  for  obser- 
vation :  but  what  have  you  now  to  do  1 

Child.  To  examine  the  animals  before  us,  to 
use  our  senses  upon  them  as  we  did  in  our  les- 
sons on  objects,  to  name  their  parts,  and  the 
uses  of  their  parts  as  far  as  we  know  them. 

Teacher.  Yes  ;  I  wish  you  first  to  observe 
these  creatures  attentively ;  and  that  you  may 
discover  readily  what  is  peculiar  to  them,  you 
must  in  your  own  minds  compare  their  qualities, 
parts,  and  habits,  with  what  you  know  of  other 
animals.  First,  however,  tell  me  some  qualities 
that  appear  to  you  to  be  common  to  all  the  mol- 
lusca. 

Child.     Their  bodies  are  soft,  fleshy,  moist, 
nd  cold. 

Teacher.  Yes,  you  remember  their  name  is 
given  to  them  from  their  s6ftness.  Observe 
also  the  action  of  a  snail  when  an  enemy 
approaches. 


MOLLUSCA.  13 

Child.  It  draws  its  body  into  its  shell  for 
protection. 

Teacher.  Yes.  The  bodies  of  the  mollusca 
are  contractile,  that  is,  have  a  strong  power  of  con- 
traction, which  they  exercise  by  means  of  muscles. 
What  more  do  you  remark  in  these  creatures  ? 

Child.  They  have  a  thick  skin,  which  appears 
loose  in  some  of  them. 

Teacher.  This  skin  is  called  the  sac  or  man- 
tie  ;  it  is  peculiar  to  the  molluscous  tribe,  and  is 
constantly  moistened  by  a  slimy  exudation.  It 
is  also  full  of  pores  and  glands,  of  which  I  shall 
have  occasion  to  speak  in  a  future  lesson.  Can 
you  explain  the  nature  of  pores  and  glands  1 

Child.  Pores  are  very  small  holes.  I  do  not 
exactly  know  what  glands  are  ;  but  we  have 
glands  in  our  throats,  are  those  of  the  mollusca 
the  same  as  ours  ? 

Teacher.  They  are  of  the  same  nature,  but 
much  smaller  than  those  in  our  throats.  The 
office  of  glands  is  to  secrete  or  separate  fluids  of 
various  kinds  from  the  general  fluid  of  the  sub- 
stance. All  bodies  both  of  the  animal  and  vege- 
table kingdom  are  supplied  with  a  great  number 
of  glands ;  tears  in  animals  are  an  example  of 
secretions  formed  by  means  of  such  organs,  so  are 
honey  and  all  other  peculiar  juices  of  plants.  As 
the  glands  form  little  reservoirs,  they  often  ap- 
pear like  small  swellings,  perceptible  to  the  sight 
and  touch.  To  return  to  the  mantle  ;  it  some- 
times envelops  the  mollusca  like  a  purse,  leaving 
an  opening  only  where  the  mouth  is  situated ;  in 
some  it  extends  on  the  two  sides,  forming  ex- 
2 


14  LESSON    I. 

pansions  which  perform  the  part  of  fins.  Some- 
times it  spreads  over  the  shell  itself,  which  in 
this  case  has  always  a  fine  polish.  Remember 
I  desired  you  not  only  to  examine  the  mollusca, 
but  to  compare  them  with  other  animals.  What 
further  peculiarity  do  you  discover  in  them  1 

Child.  They  have  no  bones,  their  bodies  are 
only  a  mass  of  soft  flesh. 

Teacher.  They  have  certainly  no  bones  ;  but 
in  the  mollusca  which  we  purpose  studying,  the 
shell,  by  acting  as  a  support  to  the  body,  seems 
in  some  measure  to  answer  the  purpose  of 
bones.  What  more  do  any  of  you  discover  in 
these  animals  ? 

Child.    They  do  not  appear  to  have  any  blood, 

Teacher.  They  have  not  red  blood  as  we 
have  ;  but  are  they  composed  entirely  of  solid 
matter  ? 

Child.  No,  for  when  a  snail  is  trodden  upon, 
a  white  fluid  issues  from  it ;  is  this  its  blood  ? 

Teacher.  Yes,  it  may  be  considered  as  a  kind 
of  blood.  How  does  it  differ  from  that  which 
circulates  through  our  bodies  1 

Child.     It  is  white  and  cold. 

Teacher.  True  ;  and  in  consequence  some 
naturalists  have  not  considered  it  as  blood,  and 
have  described  the  mollusca  to  be  exsanguin- 
eous ;  a  term  signifying  without  blood,  and 
derived  from  Latin  ex,  out  of,  and  sanguine, 
blood.  As  this  fluid  flows  through  their  bodies 
in  vessels  issuing  from  their  hearts,  it  is  now 
generally  called  their  blood.  What  are  you 
watching  in  the  snail  ? 


MOLLUSCA.  15 

Child.  The  very  quick  manner  in  which  it 
draws  in  its  horns,  and  shrinks  into  its  shell,  if  it 
is  touched. 

Teacher.  What  would  you  determine  with 
respect  to  the  animal  from  this  circumstance  ] 

Child.     That  it  has  the  sense  of  feeling. 

Teacher.  Yes ;  and  which  part  appears  most 
sensitive  ? 

Child.     The  horns. 

Teacher.  And  do  you  observe  how  the  little 
animal  feels  about,  and  tries  with  these  projec- 
tions which  you  call  horns  1  They  have  from 
thence  been  termed  Tentacula,  from  the  Latin, 
tentare,  to  try  or  feel.  How  many  tentacula 
have  snails  ? 

Child.     Four. 

Teacher.  The  tentacula  vary  in  number ; 
many  mollusca  have  only  two.  The  sense  of 
feeling  resides  in  the  nerves. 

Child.  Oh  !  then  the  mollusca  must  have 
nerves. 

Teacher.  Yes  they  have  nerves.  What  other 
organ  of  sense  besides  the  tentacula  do  you  per- 
ceive ? 

Child.  There  are  black  specks  on  the  horns 
of  the  snail  which  appear  like  eyes. 

Teacher.  These  specks  are  the  organs  of 
sight,  of  which  the  mollusca  have  never  more 
than  one  pair.  The  sense  of  seeing,  however, 
is  not  universally  possessed  by  this  class  of  ani- 
mals. The  organs  of  hearing  and  smelling  have 
never  been  discovered  among  them,  but  they  are 
supposed  to  possess  the  latter  from  the  readiness 


16  LESSON   I. 

with  which  they  select  suitable  food.  This  cir- 
cumstance also  proves  that  they  possess  the 
sense  of  taste.  You  must  now  recapitulate  all 
that  has  been  said  concerning  the  mollusca. 
Whence  is  the  name  derived  1 

Child.     From  mollis,  the  Latin  for  soft. 

Teacher.     What  kind  of  body  have  they  1 

Child.     Cold,  slimy,  soft,  and  fleshy. 

Teacher.  Yes ;  and  another  quality  you 
observed  when  I  touched  the  snail  several 
times. 

Child.     That  its  body  is  contractile. 

Teacher.  And  what  enabled  it  so  quickly  to 
contract  its  body,  and  retreat  into  its  shelter  1 

Child.     Its  being  furnished  with  muscles. 

Teacher.  When  you  compare  these  animals 
with  others,  in  what  respect  do  they  appear 
deficient  ? 

Child.  They  have  no  bones,  the  shell  acting 
as  a  support  to  their  bodies,  which  are  attached 
to  it  by  muscles. 

Teacher.     What  envelops  the  mollusca  ? 

Child.     A  sac  or  mantle. 

Teacher.     Describe  the  mantle. 

Child.  The  mantle  is  full  of  pores  and 
glands,  and  is  moistened  by  a  slimy  exudation — 
sometimes  it  quite  encloses  the  animal,  having 
only  one  opening  like  a  purse,  sometimes  it  has 
expansions  at  the  side,  like  fins,  and  sometimes 
it  spreads  over  the  shell. 

Teacher.     What  are  glands  ? 

Child.  Small  lumps  containing  fluids,  which 
are  separated  from  the  blood. 


MOLLUSCA.  17 

Teacher.  Yes,  in  animals  the  glands  contain 
fluids  secreted  from  the  blood ;  but  in  vegetables 
from  the  sap.  Have  these  animals  any  fluid 
answering  to  our  blood  ? 

Child.     Yes  ;  but  it  is  white  and  cold. 

Teacher.  In  what  respects  is  it  similar  to 
blood  ? 

Child.  It  circulates  through  the  body  in  ves- 
sels issuing  from  the  heart. 

Teacher.  What  senses  are  enjoyed  by  the 
mollusca  ] 

Child.  The  senses  of  feeling,  seeing,  tast- 
ing, and,  it  is  supposed,  smelling. 

Teacher.  In  what  part  of  their  frames  is  the 
sense  of  feeling  most  acute  ? 

Child.     In  the  tentacula, 

Teacher.    Tell  me  the  derivation  of  that  term? 

Child.  It  is  derived  from  the  Latin,  Tentare, 
to  try. 

Teacher.  But  what  must  they  possess  in 
order  to  be  able  to  feel  ? 

Child.     Nerves. 

Teacher.  I  will  now  read  to  you  a  summary 
of  your  lesson,  and  I  shall  expect  you  afterwards 
to  write  it  from  recollection. 

Teacher.  The  mollusca  have  soft,  slimy, 
cold,  fleshy,  and  contractile  bodies.  They  have 
no  bones,  but  their  shell  acts  as  a  support  to  their 
frame.  They  have  muscles  by  which  they  are 
attached  to  their  shells,  and  by  which  they  move 
their  bodies.  They  are  enclosed  in  a  skin  called 
the  mantle,  or  sac,  which  is  full  of  pores  and 
glands.  Sometimes  the  animal  is  so  completely 
2* 


18  LESSON   II. 

enveloped  in  this,  as  only  to  present  an  opening 
where  the  mouth  is  situated,  sometimes  it  spreads 
over  the  shell,  and  sometimes  it  has  external  ex- 
pansions answering  the  purpose  of  fins.  The 
mollusca  have  not  warm  red  blood,  but  a  white 
cold  fluid  issues  from  their  hearts  and  circulates 
through  their  frames.  They  have  nerves,  and 
consequently,  feeling;  and  this  sense  seems 
most  acute  in  their  tentacula.  Some  have  eyes, 
but  others  do  not  enjoy  the  sense  of  sight.  They 
appear  to  have  the  power  of  smelling  and  tast- 
ing, but  no  traces  of  ears  have  been  discovered.* 


LESSON  II. 

To  commence  with  a  repetition  of  the  summary  of 
the  former  lesson.) 

Teacher.  Examine  these  animals  again, 
compare  them  with  insects,  and  tell  me  if  you 
observe  any  deficiency  in  their  construction. 

*  This  little  summary  of  the  substance  of  the  lesson  may  be  read 
over  twice  to  the  children,  and  they  should  then  be  required  to 
write  it  as  well  as  they  can  from  recollection.  It  would  be  well  also 
that  they  should  repeat  it  at  the  commencement  of  the  succeeding 
lesson.  This  process  may  appear  tedious,  but  the  result  will  be 
most  satisfactory  both  to  the  teacher  and  pupils.  The  latter  should 
acquire  so  clear  a  knowledge  of  the  facts  brought  before  them,  and 
have  them  so  well  imprinted  on  their  minds,  that  they  may,  through 
all  their  progress,  be  enabled,  without  confusion  or  hesitation,  to 
recur  to  each  preceding  step.  Their  information  should  be  like  a 
chain,  which  is  held  unbroken  in  the  grasp  j  and  were  such  the 
case,  a  power  of  mind  would  be  elicited  which,  independently  of 
the  value  of  the  knowledge  obtained,  woind  prove  its  worth  when 
applied  to  more  important  subjects. 


MOLLUSCA.  19 

Child.      They  have  not  any  limbs. 

Teacher.  Very  true.  They  have  not  limbs 
or  joints,  as  insects,  nor  are  they  divided,  or 
moved  by  means  of  rings,  as  worms. 

Child.  Yet  they  move  about. 

Teacher.  Yes ;  the  greater  part  of  the  mol- 
lusca  have  the  power  of  locomotion  ;  that  is,  the 
power  of  moving  from  place  to  place  ;  it  is  de- 
rived from  Latin  locus,  a  place.  We  will  first 
examine  the  organs  by  means  of  which  it  is  ex- 
ercised. In  what  manner  do  snails  and  slugs 
make  their  way  along  the  ground  ? 

Child.  Their  skin  seems  to  expand  at  the 
side  of  the  body,  and  to  adhere  to  the  earth,  and 
then  they  draw  themselves  on. 

Teacher.  This  fleshy  expansion  under  their 
bodies  is  full  of  muscles,  which  they  dilate  and 
contract  at  pleasure.  It  adheres  like  a  sucker, 
and  the  animal  advances  by  fixing  the  fore  part 
to  the  ground  and  drawing  the  remainder  after 
it.  This  instrument  is  called  a  foot.  In  some 
species,  as  the  snail,  it  is  attached  to  the  under 
part  of  the  body  by  its  whole  length,  but  in  others 
it  is  free  at  one  end,  and  can  be  extended  or 
withdrawn  at  pleasure.  When  it  is  free  it  is 
called  a  leg,  and  is  usually  tongue-shaped  ;  it  is 
frequently  used  as  an  organ  of  motion,  but  some- 
times the  animal  employs  it  as  a  paw  for  digging 
holes  in  the  sand  or  mud.  But  consider  whether 
this  organ  will  enable  the  mollusca  to  advance  in 
all  the  situations  in  which  they  are  placed  ? 

Child.  No,  not  when  they  are  in  the  we.ter ; 
then  they  must  swim. 


20  LESSON    II. 

Teacher.  Yes,  and  this  action  is  performed 
either  by  the  serpentine  movements  of  the  foot 
and  body,  or  by  the  movement  of  expanded  por- 
tions of  the  skin  or  tentacula,  which  forces  them 
onwards  in  the  same  manner  as  oars  propel  a 
boat. 

Child.  Have  all  the  mollusca  that  live  in  the 
water  either  tentacula  or  expansions  of  the  skin  ? 

Teacher.  No,  some  have  no  such  elongated 
parts.  I  think  you  might  have  discovered  this 
yourselves  by  observing  one  of  the  animals  be- 
fore you. 

Child.  Oh  yes,  the  oyster.  Such  mollusca 
cannot  move  them. 

Teacher.  That  is  not  true  of  all  such  mol- 
lusca; some  are  immoveably  attached  to  the 
spot  where  they  first  received  life ;  but  others 
have  the  power  of  leaping  or  shifting  their  posi- 
tion with  a  sudden  jerk,  produced  by  rapidly 
shutting  the  two  pieces  of  their  shells  ;  others 
again  transport  themselves  from  one  spot  to 
another  by  the  force  with  which  they  draw  in  and 
eject  the  fluid  in  which  they  live.  Many  species 
are  furnished  with  a  kind  of  bladder,  by  inflating 
or  contracting  which  they  can  rise  or  sink  in  the 
water  as  circumstances  require.  Enumerate  to 
me  the  various  means  of  locomotion  possessed 
by  the  mollusca. 

Child.  Many  creep  by  means  of  a  fleshy 
elongation,  which  is  in  some  a  foot,  in  others  a  leg. 
In  the  water  they  swim,  making  their  way  either 
by  the  serpentine  movement  of  their  bodies,  or 
by  the  use  of  tentacula.  Some  can  rise  and  sink 


MOLLUSCA.  21 

in  the  sea,  and  some  leap  by  rapidly  closing  their 
shells,  or  by  drawing  in  water  and  suddenly 
forcing  it  out  again. 

Teacher.  When  we  consider  the  different 
kinds  of  mollusca,  I  shall  speak  to  you  more 
fully  of  their  peculiar  habits.  Have  you  ever 
observed  when  you  have  been  on  the  sea-coast, 
numerous  shells  clustered  together  on  the  rocks 
and  stones. 

Child.  Yes,  barnacles  ;  are  they  the  animals 
which  never  move  from  the  spot  to  which  they 
are  attached? 

Teacher.  Yes,  the  barnacles,  and  many  other 
mollusca  never  quit  the  spot  where  their  exist- 
ence commenced. 

Child.     How  are  they  fixed  to  the  spot  ? 

Teacher.  Some  of  them,  as  the  barnacles, 
are  cemented  to  the  rocks  by  the  same  substance 
of  which  their  shells  are  formed  ;  others  have  a 
less  permanent  mode  of  adhesion,  and  fasten 
themselves  by  means  of  a  viscid  liquid  which 
they  discharge  from  glands  in  their  bodies ;  some 
produce  silky  filaments,  one  extremity  of  which 
remains  in  connexion  with  themselves,  while  the 
other  is  fixed  to  marine  substances,  and  thus  an- 
choring themselves,  they  float  secure  in  the 
ocean.  The  bundle  of  filaments  which  the  ani- 
mal draws  from  his  body  for  this  purpose  is 
called  a  byssw.*  Do  you  know  any  other 


22  LESSON   I. 

shells  that  are  with  difficulty  removed  from  the 
rocks  ? 

Child.     Yes,  the  limpet. 

Teacher.  The  manner  in  which  the  animal 
you  mention  fixes  itself  upon  rocks,  is  very 
simple,  though  very  curious.  It  forms  within  its 
shell  a  vacuum,  that  is,  a  space  free  from  air, 
derived  from  Latin  vacuws,  free.  By  filling  up 
the  hollow  of  its  shell  with  the  fleshy  substance 
of  its  body,  it  expels  the  air,  and  having  fastened 
its  body  to  the  rock  by  a  viscid  substance,  con- 
tracts itself  in  the  centre,  thus  leaving  a  space 
within  the  shell  entirely  free  from  air.  As  there 
then  is  no  internal  expansion  of  this  fluid,  the 
pressure  of  the  external  atmosphere  meets  with 
no  resistance,  and  in  consequence  acts  with  so 
much  force  upon  the  shell,  that  it  cannot  be  re- 
moved from  its  situation  without  great  effort. 
Repeat  to  me  now  the  different  means  of  attach- 
ment used  by  the  mollusca. 

Child.  Some  fix  themselves  by  silky  fila- 
ments called  a  byssus,  some  by  a  viscid  cement, 
others  by  forming  a  vacuum,  and  others  attach 
themselves  to  the  rocks  by  the  same  substance 
of  which  their  shells  are  made. 

Teacher.  The  shells  which  by  any  of  these 
means  are  rendered  stationary,  are  called  fixed 
shells,  the  others  free  shells.  Does  any  thing 
strike  you  with  regard  to  these  two  kinds  01 
mollusca  ? 

Child.  The  inhabitants  of  the  fixed  shells 
must  be  badly  ofT.  They  cannot  procure  nou^ 
rishment. 


MOLLUSCA.  23 

Teacher.  They  cannot  indeed  go  in  search 
of  it,  but  the  continued  motion  of  the  waves,  or 
the  flowing  of  the  tide,  brings  a  fresh  supply  of 
water  swarming  with  the  little  animals  upon 
which  they  subsist,  and  some  increase  the  rapid- 
ity of  this  supply,  by  forming  currents  in  the  sea. 

Child.  What  very  clever  contrivers  these 
animals  seem  to  be. 

Teacher.  Yes,  and  your  remark  leads  me  to 
an  important  consideration,  to  which  I  wish  to 
direct  your  attention.  How  do  these  little  ani- 
mals know  that  it  is  well  for  them  to  attach 
themselves  to  other  substances.  How  have  they 
learned  to  form  the  vacuum,  or  weave  the  silken 
filaments  1 

Child.     Is  it  not  instinct  that  directs  them  ? 

Teacher.  Yes,  but  can  you  tell  me  what  in- 
stinct is  ? 

Child.  It  is  something  that  guides  animals. 

Teacher.     Is  man  taught  in  the  same  way  1 

Child.  No,  we  have  reason,  and  can  think 
about  what  we  do. 

Teacher.  Well,  let  us  consider  a  little  the 
difference  between  that  which  directs  man,  and 
that  which  guides  other  animals.  Suppose  a 
child  were  to  see  a  fire  for  the  first  time  :  not 
knowing  its  nature,  he  might  perhaps  put  his 
finger  into  it.  Would  he  do  so,  do  you  think,  a 
second  time? 

Child.  No,  he  would  recollect  the  conse- 
quences of  having  done  so  before. 

Teacher.  He  would  have  learned  then  from  his 
own  experience  ;  but  is  all  knowledge  obtained 


24  LESSON   II. 

by  our  own  experience  ;  do  you  not  know  any 
thing  but  what  you  have  discovered  yourself? 

Child.  We  learn  from  the  accounts  of  others. 

Teacher.  True,  we  are  instructed  by  the 
experience  of  others.  But  watch  any  animal, 
a  bee,  for  instance  ;  when  he  makes  his  cell, 
does  he  try  several  times  before  he  succeeds  ? 

Child.  No,  he  does  it  perfectly  at  the  first 
attempt. 

Teacher.  Has  he  been  taught  by  his  own 
species  ? 

Child.     No. 

Teacher.  What  then  is  the  difference  between 
the  principle  that  guides  the  bee,  and  that  which 
guides  man? 

Child.  Man  is  taught  both  by  his  own  ex- 
perience, and  that  of  others ;  but  the  bee  acts 
rightly  without  either. 

Teacher.  Yes ;  he  is  directed  immediately 
by  a  principle  implanted  in  him  by  the  Creator. 
This  principle  is  called  instinct,  and  is  well 
defined  to  be  prior  to  experience,  and  independ- 
ent of  instruction.  I  will  now  read  to  you  the 
summary  of  to-day's  lesson — attend,  that  you 
may  be  able  to  write  it  out  from  recollection. 

Summary. 

Many  of  the  mollusca,  though  destitute  of 
jointed  limbs,  have  organs  of  motion ;  some 
have  a  fleshy  expansion  extending  the  length  of 
the  body,  called  a  foot ;  this  instrument  is  full 
of  muscles,  by  which  it  is  moved ;  it  acts  like  a 
sucker,  and  the  animal  advances  by  fixing  the 


MOLLUSCA.  25 

fore  part  to  the  ground,  and  drawing  the  re- 
mainder after  it.  This  organ  is  sometimes  free, 
and  can  be  extended  or  contracted  at  pleasure  ; 
it  is  then  called  a  leg,  and  is  used  either  as  an 
organ  of  motion,  or  as  a  paw  for  digging  holes 
in  the  sand  or  mud.  In  the  water,  the  mollusca 
advance  either  by  means  of  the  serpentine  move- 
ment of  their  bodies,  or  by  the  movement  of 
either  expanded  portion  of  the  skin  or  tenta- 
cula.  Some,  quite  destitute  of  any  separate 
organs  of  motion,  effect  a  change  in  their  po- 
sition by  ingenious  contrivances ;  thus,  the  com- 
mon scallops,  by  rapidly  shutting  the  two  pieces 
of  their  shell,  can  transport  themselves  a  short 
distance  ;  and  others  propel  themselves  by  draw- 
ing in  water  arid  ejecting  it  again  with  great 
force.  Many  species  are  furnished  with  a  kind 
of  air-bladder,  by  inflating  or  contracting  which, 
they  rise  and  sink  in  the  water  as  circumstances 
may  require.  Some,  however,  have  no  power 
at  all  of  moving,  but  remain  fixed  through  life  to 
the  spot  where  they  commenced  their  existence. 
Their  modes  of  attachment  vary  ;  some  firmly 
fix  themselves  by  the  same  materials  of  which 
they  make  their  shells  ;  others  glue  themselves 
by  a  viscid  cement  drawn  from  glands  in  their 
bodies ;  and  others  throw  out  a  byssus,  and 
anchor  themselves  securely  to  some  rock.  The 
limpet,  by  forming  a  vacuum  in  his  shell,  main- 
tains a  firm  hold  of  marine  substances.  The 
shells  thus  rendered  stationary,  are  called  fixed 
shells,  whilst  those  inhabited  by  animals  that 
move  about,  are  termed  free  shells. 
3 


26  LESSON  III. 

LESSON  III. 
(Repetition  of  the  preceding  summary  as  usual.} 

Teacher.  What  organs  in  the  mollusca  have 
we  taken  into  consideration  ? 

Child.     The  organs  of  sense  and  of  motion. 

Teacher.  And  what  other  organs  are  essential 
to  animal  existence  ? 

Child.  All  animals  must  have  organs  by 
which  they  feed  themselves. 

Teacher.  Have  you  ever  observed  snails 
eating  ? 

Child.  Yes ;  I  have  seen  them  devour  a 
leaf,  and  I  should  think  they  must  have  teeth. 

Teacher.  They  have  two  jaws  which  are 
furnished  with  small  teeth,  fitted  for  cutting 
vegetable  substances. 

Child.  Have  all  the  mollusca  mouths  like 
that  of  the  snail  ? 

Teacher.  No,  the  mouths  of  each  species, 
as  well  as  their  other  organs,  are  adapted  to  their 
peculiar  wants  and  habits.  Some  have  only  a 
simple  opening  to  receive  the  little  animalcula 
brought  to  them  by  the  waves,  and  which  do 
not  require  mastication.  Most  of  those  which 
live  upon  the  produce  of  the  vegetable  kingdom 
have  a  muzzle  with  jaws  which  are  either  horny 
or  armed  with  teeth.  The  carnivorous*  mol- 
lusca have  usually  a  kind  of  proboscis ;  this 

*  From  the  Latin  corne,J?esA,  and  toro,  I  eat. 


MOLLUSCA.  27 

instrument  is  a  fleshy  pliable  tube,  terminated 
by  a  round  aperture,  with  a  cartilaginous  edge 
armed  with  little  teeth.  The  proboscis  is  sup- 
plied with  muscles,  by  which  the  animal  can 
protrude  and  draw  it  in  at  pleasure.  Many  use 
it  to  pierce  the  shells  of  other  mollusca,  that 
they  may  suck  out  the  flesh  of  the  inhabitant. 
The  mollusca  possess  also  different  means  of 
bringing  their  food  to  their  mouths  ;  some  make 
use  of  tentacula  to  grasp  their  prey;  others 
stretch  out  their  proboscis  ;  and  some,  you  re- 
member, insure  a  frequent  supply  of  food  by 
creating  an  eddy  in  the  water.*  I  should  like 
you  now  to  compare  the  oyster  and  the  snail 
together,  and  tell  me  what  you  consider  to  be 
the  most  striking  difference  between  them. 

Child.  The  snail  has  a  head,  but  the  oyster 
appears  only  a  lump  of  flesh  without  any  division 
in  its  body. 

Teacher.  This  is  the  case  with  a  large  num- 
ber of  mollusca ;  they  have  no  obviously  distinct 
head.  This  circumstance  has  induced  naturalists 
to  divide  them  into  two  great  classes.  What  do 
you  think  they  are  ? 

Child.  One  class  would  consist  of  those 
animals  which  have  heads ;  the  other  of  those 
destitute  of  heads. 

Teacher.  The  former  are  called  mollusca 
ctphala,  from  the  Greek  K^aA?  (kephale)  a  head ; 
the  latter,  mollusca  acephala,  from  the  Greek  a 


*  The  children  should  give  a  recapitulation  of  this  account  of  the 
animal.  It  may  either  be  a  viva  voce  repetition,  or  written  on  their 
•lates. 


ZO  LESSON  III. 

without,  and  K^aAi?  a  head.  Jhe  mollusca  ace- 
phala  have  no  distinct  head,  nor  any  appear- 
ance either  of  the  organs  of  sight  or  hearing ; 
their  mouth  is  only  a  simple  opening  for  the 
reception  of  their  food.  They  all  inhabit  the 
water.  Their  shells  are  composed  of  two  pieces 
united  by  a  hinge,  and  the  animals  are  attached 
to  them  by  muscles  which  pass  through  their 
bodies,  and  by  means  of  which  they  open  and 
shut  them.  Many  of  the  species  have  no  power 
of  locomotion,  and  their  organization  is  alto- 
gether very  inferior  to  the  mollusca  cephala. 
Do  you  remember  any  instances  of  this  class  ? 

Child.  The  oyster  and  the  muscle  must 
belong  to  the  mollusca  acephala. 

Teacher.  Yes.  You  must  now  endeavour  to 
recollect  all  that  we  have  said  about  the  mol- 
lusca. I  will  arrange  the  matter,  and  write  it  on 
the  slate,  and  you  shall  afterwards  commit  it  to 
memory. 

Mollusca. 

The  mollusca  have  a  soft,  cold,  slimy,  and 
contractile  body  moved  by  muscles.  They  have 
no  articulated  moveable  parts  as  limbs ;  the  prin- 
cipal organs  of  motion  are  tentacula  of  different 
forms,  and  answering  various  purposes.  Some 
have  a  fleshy  foot  extending  along  the  under  par  t 
of  their  bodies ;  in  others  the  fleshy  substance  is 
free  and  pliable,  and  can  be  projected  and  drawn 
in  at  pleasure.  Their  bodies  are  enveloped  in 
a  sac  or  mantle  of  skin,  full  of  pores  and  glands, 
which  sometimes  spreads  over  their  shell.  They 


MOLLUSCA.  29 

are  destitute  of  bones.  They  have  not  red  warm 
blood,  but  a  white  cold  fluid  circulates  through 
their  frames  in  vessels  issuing  from  the  heart. 
They  have  nerves  connected  with  their  different 
organs.  They  are  divided  into  two  classes. 
The  first,  mollusca  cephala,  have  a  distinct 
head,  bearing  lips  or  jaws,  and  are  furnished 
with  eyes  and  tentacula.  The  second,  mollusca 
acephala,  have  a  more  simple  organization ; 
they  have  no  distinct  head,  and  are  destitute  of 
jaws  and  other  hard  parts  of  a  mouth ;  they 
inhabit  shells  formed  of  two  pieces. 


LESSON  IV. 

(Shells.) 

Teacher.  Well,  did  you  find  the  study  of  the 
mollusca  as  uninteresting  and  unprofitable  as 
you  expected  it  to  be  ? 

Child.  Oh,  no,  we  have,  on  the  contrary, 
learnt  much  that  has  interested  and  surprised  us. 

Teacher.  And  what  useful  lesson  may  you 
apply  to  yourselves  from  the  mistake  you  first 
made? 

Child.  Not  to  look  upon  any  of  the  works  of 
God  with  indifference  or  contempt,  but  to  feel 
convinced  that  if  they  fail  to  excite  our  admira- 
tion, it  is  on  account  of  our  ignorance. 

Teacher.  The  more  you  study  Natural 
History,  the  more  you  will  be  inclined  to 
acknowledge  this  truth.  Now  I  wish  you  to 
3* 


SO  LESSON  IV. 

examine  the  coverings  of  the  mollusca, — are 
there  any  parts  of  other  animals  that  can  be 
compared  to  shells  ? 

Child.  The  hard  coverings  of  beetles  are 
something  like  them. 

Teacher.  What  strikes  you  as  being  the 
principal  difference  between  shells  and  the  case 
in  which  some  insects  are  enclosed] 

Child.  Shells  are  distinct  from  the  mollusca, 
as  if  they  were  their  houses ;  but  the  coverings  of 
insects  fit  the  different  members  of  their  bodies 
like  a  skin,  and  seem  to  be  a  part  of  the  animal 
itself. 

Teacher.  The  coverings  of  insects  are  united 
to  their  different  members ;  but  shells  are  at- 
tached to  the  mollusca  only  in  one  or  two  places 
by  muscles.  You  must  have  had  the  opportunity 
of  observing  how  they  adhere  in  one  spot  to 
their  shell. 

Child.  Yes,  you  are  obliged  to  cut  the  oyster 
away  from  the  shell. 

Teacher.  Besides  the  difference  which  you 
have  observed  in  these  two  coverings,  their 
composition  is  not  the  same.  You  remember 
learning  in  your  lessons  on  lime,*  the  animal 
substances  of  which  it  forms  the  principal  part. 

Child.  Yes,  our  bones  consist  principally 
of  carbonate  of  lirne,  and  I  think  you  said  that 
shells  were  also  a  calcareous  substance. 

Teacher.  Shells  are  composed  of  carbonate 
of  lime,  with  the  addition  of  a  small  portion  of 

*  See  Lessons  on  Objects,  page  173,  Third  Edition. 


MOLLUSCA.  31 

an  animal  substance  called  gelatine:  the  covering 
of  insects  is  a  phosphate  of  lime.  The  substance 
of  shells  is  testaceous,  having  the  hardness  of 
baked  earthenware,  in  Latin,  test  a;  and  hence 
the  mollusca  enclosed  in  them  are  called  testa- 
ceous mollusca:  the  covering  of  insects  is  crus- 
taceous,  having  the  hardness  of  crust,  in  Latin, 
crust  a. 

Child.  But  whence  is  the  carbonate  of  lime, 
of  which  shells  are  composed,  obtained?  Is  it 
found  in  the  sea? 

Teacher.  It  exudes  from  the  skin  of  the 
animal,  which,  as  I  told  you,  is  furnished  with 
numerous  glands.  In  these  is  secreted  the  cal- 
cereous  matter. 

Child.  How  very  wonderful  that  they  should 
thus  be  provided  with  materials  to  make  their 
abode ;  but  how  is  the  shell  formed  from  this 
substance"? 

Teacher.  The  little  animal  you  formerly 
despised  is  its  own  architect,  and  constructs  a 
dwelling  exactly  suited  to  its  wants.  One  of  our 
divines,  who  has  written  a  volume  to  show  that 
the  works  of  creation  are  alone  sufficient  to 
prove  the  existence  of  a  wise  and  beneficent 
God,  says,  speaking  of  a  shell,  "  I  do  not  know 
whether  weight  being  given,  art  can  produce  so 
strong  a  case  as  some  shells."* 

What  do  you  now  think  of  the  workmanship 
of  these  little  creatures  1 

Child.     It  is  very  wonderful,  how  remarkable 

•  Paley's  Natural  Theology. 


33  LESSON   IV. 

that  there  should  be  such  a  variety  of  shapes  m 
shells  ? 

Teacher.  The  shape  of  the  shell  is  deter- 
mined by  that  of  the  animal  itself. 

Child.  But  the  mollusca  do  not  always  con- 
tinue the  same  size. 

Teacher.  Very  true.  They  are  quite  minute 
when  they  come  out  of  the  egg,  and  the  shell  is 
then  proportionably  small ;  but  as  the  animals 
increase  in  size,  they  add  to  the  dimensions  of 
their  shells  by  additions  made  at  the  opening, 
and  to  its  thickness  by  a  succession  of  layers 
deposited  within. 

Child.  Do  they  always  construct  their  shells 
of  the  proper  shape  1 

Teacher.  Yes,  the  carpenter  with  his  rule 
and  compass  is  not  so  exact  and  unerring  as 
these  heaven- taught  builders.  But  is  form  the  only 
point  that  attracts  your  attention  in  these  shells  ? 

Child.  Oh  no  ;  they  have  most  beautiful 
colours  and  markings  ;  these  cannot  belong  to 
the  carbonate  of  lime. 

Teacher.  No,  and  again  I  must  excite  your 
admiration  of  the  little  animal,  which,  while  he 
constructs,  also  adorns  his  habitation.. 

Child.  But  whence  can  he  procure  such 
beautiful  colours  1 

Teacher.  He  is  furnished  in  himself  with  all 
that  is  necessary  both  for  the  constructing  and 
beautifying  his  shell ;  his  skin  you  remember  is 
full  of  pores  ;  these  contain  colouring  fluids, 
which,  penetrating  the  calcareous  substance  be- 
fore it  is  hardened,  form  its  diversified  tints. 


MOLLUSCA.  33 

Child.  It  seems  very  wonderful  that  so 
many  shells  should  have  the  same  pattern. 

Teacher.  It  is  indeed  most  wonderful.  I  can 
telly  ou  however  how  it  is  supposed  to  be  effected. 
The  pores  containing  the  colouring  matter  are 
arranged  in  the  skin  of  the  mollusca  with  the 
same  undeviating  regularity  as  the  spots  upon 
the  leopard,  or  the  stripes  upon  the  tiger,  and 
when  the  liquid  exudes,  it  stains  the  shell,  and 
the  uniformity  of  the  pattern  is  the  consequence 
of  the  order  in  which  the  pores  are  placed  in  the 
mantle.  Now  look  at  all  these  shells,  and  con- 
sider them  only  in  reference  to  their  colours  and 
markings. 

Child.  The  colours  in  some  are  very  beau- 
tiful, and  there  is  great  variety  of  patterns. 

Teacher.  This  is  very  true ;  but  are  they  all 
different  ? 

Child.  No,  there  are  some  that  have  quite 
the  same  pattern. 

Teacher.  Then  you  may  observe  two  points, 
especially  with  regard  to  the  markings  ;  what 
are  they  1 

Child.  That  there  is  a  very  great  variety, 
and  yet  some  are  alike. 

Teacher.  Yes,  a  variety  and  uniformity  most 
wonderful ;  but  do  you  suppose  that  their  being 
alike  is  accidental  ? 

Child.  Oh  no,  it  could  not  have  arisen  from 
chance. 

Teacher.  Very  true,  nor  can  we  fail  to  ob- 
serve, that  however  great  the  variety  may  be  in 
individual  specimens,  all  the  works  of  creation 


34  LESSON    IV. 

present  a  beautiful  principle  of  order  and  uni- 
formity. Prove  if  you  quite  understand  what  I 
mean,  by  applying  it  to  these  shells. 

Child.  There  is  a  very  great  variety  of  pat- 
terns and  shapes,  and  yet  they  are  all  alike  in 
many  respects. 

Teacher.  They  have  undoubtedly  all  a  ge- 
neral resemblance,  which  enables  you  at  once  to 
determine  that  they  are  shells ;  but  more  than 
this,  do  you  not  observe  that  some  are  more  alike 
than  others  ? 

Child.  There  are  some  that  are  very  much 
alike  in  shape. 

Teacher.  Yes,  and  yet  differ  in  other  re- 
spects ;  but  is  this  all  that  you  observe  1 

Child.  No,  there  are  some  that  appear  ex- 
actly alike. 

Teacher.  Thus  when  you  look  at  a  collection 
of  shells  for  the  first  time,  you  are  struck  by  their 
general  similarity,  and  you  at  once  call  them  all 
shells.  After  a  little  inspection,  it  will  be  evi- 
dent that  among  them,  some  have  a  few  points 
of  resemblance,  and  that  others  are  quite  alike  in 
all  respects.  Thus  you  begin  to  perceive  that 
the  variety  which  at  first  almost  bewildered  you, 
is  limited  by  a  principle  and,  while  your  eye  is 
gratified  by  the  diversity,  your  judgment  is  satis- 
fied by  the  order  you  find  preserved.  Tell  me 
a  similar  circumstance  in  some  other  natural 
objects. 

Child.  Flowers  afford  one.  All  roses  are 
alike  in  general  appearance,  but  the  Moss  Rose 
is  easily  distinguished  from  the  China  Rose. 


MOLLUSCA.  35 

Teacher.  The  variety  exhibited  in  the  works  of 
nature  cannot  fail  to  delight  us,  and  the  resem- 
blances observable  in  them  enable  us  to  classify 
and  arrange  them. 

There  is  still  one  point  with  respect  to  shells 
which  we  have  not  considered ;  I  mean  the  situ- 
ations which  they  occupy.  Where  are  shells 
found  ? 

Child.  Most  of  them  in  the  sea,  but  some  on 
land,  and  others  in  ponds  and  rivers. 

Teacher.  Those  which  live  on  land  are 
called  terrestrial,  from  the  Latin,  terr  a,  earth. 
These  rnollusca  feed  on  vegetables,  and  have 
always  four  tentacula,  and  their  eyes  are  placed 
at  the  tips  of  these  organs.  The  shells  which 
are  found  in  fresh  water,  are  called  fluviatile, 
from  the  Latin  fluvi  us,  a  river.  Their  rnollusca 
have  only  two  tentacula,  which  are  flat,  and  have 
eyes  at  the  base.  These  shells  are  generally  of 
a  corneous  colour,  and  are  semitransparent. 
The  shells  inhabiting  the  sea  are  termed  marine, 
from  the  Latin,  mar  e,  the  sea.  They  are  much 
the  most  numerous,  the  most  beautiful,  and  the 
most  highly  prized.  I  will  now  recapitulate  to 
you  the  substance  of  the  lesson  to-day,  and  you 
must  write  it  on  your  slates.* 

Shells  resemble  the  hard  coverings  of  insects  ; 
the  principal  difference  between  them  is,  that 
the  former  are  only  attached  to  the  animal  in 
one  or  two  places,  while  the  hard  case  of  insects 

*  It  would  be  desirable  before  the  recapitulation  that  the  teacher 
should  question  the  pupils  upon  the  points  that  have  been  dis 
cussed,  as  in  a  preceding  lesson. 


36  LESSON   V. 

fits  the  members  of  their  bodies,  and  has  more 
of  the  nature  of  a  skin.  The  substance  also 
differs ;  that  of  shells  is  a  carbonate  of  lime, 
with  a  small  portion  of  an  animal  substance 
called  gelatine,  and  is  termed  testaceous,  from 
test  a,  the  Latin  for  baked  earthenware.  The 
case  of  insects  is  a  phosphate  of  lime,  and  is 
called  crustaceans.  The  carbonate  of  lime,  of 
which  the  shells  are  formed,  is  secreted  in  the 
glands  of  the  mantle,  and  oozing  out,  takes  the 
form  of  the  animal,  and  gradually  hardens. 
When  the  mollusca  is  small,  the  shell  is  propor- 
tionably  so  ;  but  as  the  animal  increases,  it  adds 
to  the  dimensions  of  its  abode  by  additions  at 
the  opening,  and  to  its  thickness  by  layers  from 
within.  The  colour  and  markings  with  which 
the  shells  are  diversified  are  produced  in  the 
pores  of  the  mantle,  and  are  there  arranged  in 
the  same  pattern  as  that  which  appears  on  the 
shell.  Shells  are  either  terrestrial,  fluviatile,  or 


LESSON  V. 

Teacher.  Let  us  now  consider  in  what  situa- 
tion the  mollusca  are  placed.  They  are,  as  you 
know,  exposed  to  the  dashing  of  the  waves, 
borne  by  the  violence  of  storms  against,  rocks, 
and  carried  down  rapid  rivers.  You  can  readily 


MOLLTJSCA.  37 

imagine  the  consequences  of  their  being  situated 
amid  such  perils. 

Child.  Yes.  The  shells  must  frequently  be 
Sroken,  and  the  poor  animals  perish. 

Teacher.  Your  first  conclusion  is  true.  The 
shells  are  often  broken  or  injured  ;  but  God 
always  makes  a  suitable  provision  for  the  cir- 
cumstances under  which  he  places  his  creatures. 
Recollect  that  the  same  Almighty  Being  who 
rules  the  tempests,  directs  also  the  movements 
of  the  minutest  animals,  he  knows  every  effect 
of  the  former  upon  the  latter,  for  he  sees  all  the 
workings  of  his  mighty  plan.  I  am  sure  that 
you  must  know  from  Scripture  that  such  is  the 
case. 

Child.  Yes ;  without  Him  not  a  sparrow 
falleth  to  the  ground. 

Teacher.  This  providential  care  is  very  evi- 
dent in  the  history  of  the  mollusca.  We  find 
that  the  construction  of  the  shell  varies  accord- 
ing to  the  situation  in  which  it  is  placed.  Some 
shells  which  are  taken  from  the  rapid  rivers  of 
America,  are  fitted  by  their  great  hardness  and 
thickness  to  contend  with  the  most  boisterous 
elements  ;  others  on  the  contrary,  by  their  very 
lightness,  seem  constructed  to  float  on  the  sur- 
face of  the  sea,  and  offering  no  resistance  are 
carried  along  gently  by  its  waves.  Some  of  the 
mollusca,  by  adding  to  the  weight  of  their  little 
bark,  are  enabled  to  descend  and  seek  a  shelter 
in  the  deep  of  the  ocean ;  some,  you  have  learned, 
anchor  themselves  to  rocks  and  thus  bid  defi- 
ance to  dangers.  But  in  spite  of  all  these,  and 
4 


38  LESSON    V 

many  more  equally  beautiful  contrivances,  a 
breach  is  often  effected  in  the  habitation  of  the 
mollusca, 

Child.  And  then  the  poor  animals  must 
perish  ] 

Teacher.  This  is  by  no  means  inevitably  the 
case,  for  they  are  gifted  with  the  power  of  repair- 
ing their  shells. 

Child.     How  do  they  manage  this  ? 

Teacher.  By  a  discharge  of  the  same  cal- 
careous matter,  of  which  they  at  first  constructed 
their  shells.  You  might  by  your  own  expe- 
rience prove  that  this  is  true.  You  should  pro- 
cure in  the  spring  some  common  snails,  break 
off  a  part  of  their  shells,  then  giving  them  a  sup- 
ply of  food,  place  them  under  a  glass  that  you 
may  watch  their  operations.  You  would  ob- 
serve first  a  frothy  matter  exuding  from  that  part 
of  the  animal  you  had  uncovered  and  forming  a 
film,  in  a  short  time  a  second  discharge  would 
raise  the  first  to  the  level  of  the  external  surface 
of  the  shell,  and  by  degrees  fresh  accessions 
would  give  the  new  part  the  thickness  and  sub- 
stance of  the  old  shell. 

Child.  It  would  be  very  amusing  to  watch 
this  experiment. 

Teacher.  But  do  you  not  admire  the  instinct 
that  so  wonderfully  directs  these  little  animals 
in  their  self-preservation  ? 

Child.  It  is  very  surprising,  certainly,  that 
such  a  worm  should  have  the  power  of  remedying 
so  great  disasters.  But  could  not  God  have 
enabled  them  to  form  their  shell  at  first  too  strong 


MOLLUSCA.  39 

to  be  liable  to  injuries,  or  else  have  placed  them 
out  of  the  reach  of  danger  ? 

Teacher.  Doubtless  God  could  have  done 
either.  But  all  creation,  as  it  is  now  constituted, 
reads  us  the  lesson  which  we  ought  never  to 
forget,  that  the  work  which  was  pronounced 
"  good,"  when  it  first  came  from  the  Almighty's 
hand,  has  been  marred.  Every  where  we  trace 
the  consequences  of  the  fall — all  nature,  in  its 
tendency  to  decay,  shows  the  sentence  of  death 
passed  upon  it ;  but  yet  amid  the  sad  history  it 
proclaims,  it  bears  even  in  its  fallen  state  the 
impress  of  divine  love  and  mercy.  Now  ex- 
amine again  the  shells  before  you,  and  try  and 
discover  where  any  of  them  have  been  repaired. 

Child.  Several  appear  patched,  and  some 
have  regular  seams. 

Teacher.  These  seams  mark  where  the  animal, 
in  consequence  of  its  own  growth,  has  made  an 
addition  to  its  residence.  Observe  this  shell. 
(Buccinum  flammium.)  Can  you  not  trace  the 
gradual  extension  of  the  shell  from  a  very  small 
one  ? 

Child.  Yes,  it  is  marked  by  a'  rib  like  that 
at  the  opening. 

Teacher.  You  will  find  a  great  many  shells 
which  show  that  they  have  been  enlarged  in  the 
same  manner.  The  fresh  layers  are  parallel  to 
the  margin  of  this  opening  called  the  mouth,  and 
the  meeting  of  the  edges  of  the  new  and  old 
matter  is  often  marked  by  a  ridge  more  or  less 
elevated. 

The  shell  of  the  adult  animal  is  often  armed 


40  LESSON   V. 

with  inequalities  on  the  surfaces,  as  spines  01 
tubercles,  which  do  not  appear  in  the  young 
shell.  I  will  now  give  you  a  summary  of  the 
lesson  of  to-day. 

The  mollusca  are  often  placed  in  situations  of 
great  danger.  They  are  exposed  to  the  dashing 
of  the  waves,  often  borne  by  the  violence  of 
storms  and  cast  against  rocks  or  stones.  Others 
placed  in  rapid  rivers  are  occasionally  hurried 
along  by  the  impetuosity  of  the  stream.  God, 
however,  always  makes  a  suitable  provision  for 
the  circumstances  under  which  he  places  his 
creatures,  and  if  he  apportions  to  them  spots  of 
danger,  arms  them  with  the  means  of  protection 
and  defence.  Thus  we  find  that  the  shell  and 
the  habits  of  the  mollusca  are  adapted  to  the  si- 
tuations which  they  occupy.  Some  that  belong 
to  the  rapid  rivers  of  America  have  an  exceed- 
ingly hard  and  substantial  shell,  fitted  to  contend 
with  the  most  boisterous  elements  ;  others,  on 
the  contrary,  by  their  very  lightness  are  enabled 
to  float  on  the  surface  of  the  water,  and,  offering 
no  resistance,  are  gently  carried  along  by  its 
waves.  Some  anchor  themselves  securely  by  a 
byssus  to  rocks,  and  thus  bid  defiance  to  danger. 
Others  by  adding  to  the  weight  of  their  bark  can 
descend  and  seek  a  shelter  in  the  bed  of  the 
ocean.  There  are  many  other  beautiful  con- 
trivances for  their  preservation.  But  in  spite  of 
these  a  breach  is  sometimes  made  in  their  shell, 
and  then  they  have  the  power  of  repairing  it  by 
exuding  a  calcareous  matter,  similar  to  that  with 
which  they  at  first  constructed  it. 


SHELLS.  41 


LESSON  VI. 

Teacher.     To-day  you  shall  tell  me  all  that 
you  remember  respecting  shells.     I  will  put  it 
together  in  a  more  regular  manner,  and  you  shall 
learn  by  heart  the  written  account. 
Shells. 

Shells  are  the  coverings  or  habitations  of  a 
species  of  mollusca.  They  are  formed  by  the 
animal  himself  of  carbonate  of  lime  and  gela- 
tine :  these  substances  are  secreted  in  glands  in 
his  body.  The  colouring  matter  exudes  from  the 
pores  of  the  mantle ;  it  penetrates  the  shell  be- 
fore it  is  hardened,  and  the  colours  being  ar- 
ranged in  order  in  the  mantle,  give  the  shell  the 
peculiar  markings  which  belong  to  the  different 
species.  When  any  accident  happens  to  the 
shell,  the  animal  is  enabled  to  repair  it  in  the 
same  manner  that  he  at  first  made  it.  The  size 
of  the  shell  is  in  proportion  to  that  of  its  inhabit- 
ant ;  small  at  first,  but  continually  increasing 
till  the  animal  has  attained  his  full  size. 


Teacher.  Before  we  enter  more  fully  upon 
the  study  of  shells,  and  their  classification,  I 
wish  to  direct  your  attention  to  two  circum- 
stances very  conspicuous  in  the  works  of  the 
Creator.  The  first  is,  the  economy  displayed 
by  God  ;* — you  seem  surprised. 

Child.    Yes,  it  is  so  very  extraordinary  to  talk 

*  Paley's  Natural  Theology. 

4* 


42  LESSON   VI. 

of  God's  being  economical,  when  every  thing  is 
at  his  disposal,  and  he  can  create  at  his  plea- 
sure. 

Teacher.  Do  you  not  recollect  an  illustration 
our  Saviour  gave  of  this  principle  at  the  very 
time  that  he  was  manifesting  his  omnipotence  ? 

Child.  Yes,  after  he  had  fed  the  multitude 
with  the  two  loaves  and  five  small  fishes,  he 
commanded  that  the  fragments  should  be  ga- 
thered up,  that  nothing  be  lost. 

Teacher.  You  will  discover  the  same  prin- 
ciple displayed  in  the  works  of  creation.  Nothing 
is  superfluous  or  without  its  use.  The  second 
principle  to  which  I  wish  you  to  give  your  atten- 
tion is,  the  compensatory  Providence  of  God. 

Child.    What  does  that  mean  1 

Teacher.  To  compensate  is  to  make  amends 
for  any  defect,  or  to  give  something  of  equal 
value  for  any  thing  taken  away.  In  nature  we 
often  find  objects  in  which  there  appear  nume- 
rous deficiencies,  but  on  further  examination  we 
discover  that  these  are  compensated  or  made  up 
by  some  admirable  contrivance.  To  make  this 
clear  to  you,  we  will  reflect  upon  a  well-known 
instance.  Consider  the  spider,  what  is  its  food  ? 

Child.     Flies  and  other  insects. 

Teacher.  And  what  mode  of  pursuit  should 
you  think  best  adapted  to  catching  such  crea- 
tures ] 

Child.    Flying.    But  the  spider  has  no  wings. 

Teacher.  Here  then  appears  a  sad  deficiency : 
winged  insects  are  the  natural  food  of  the  spider, 
and  he  has  not  the  means  of  pursuing  them. 


MOLLUSCA.  43 

Yet  do  you  not  perceive  how  God  has  compen- 
sated this  deficiency  1 

Child.  Yes,  you  mean  by  teaching  him  to 
construct  a  web  to  entrap  the  flies. 

Teacher.  This  instance  will  give  you  a  good 
idea  of  what  is  meant  by  the  compensatory  pro- 
vidence of  God.  It  is  much  displayed  in  the 
singular  fitness  of  shells  for  their  respective  lo- 
calities. Those  which  move  easily  from  place 
to  place,  and  consequently  are  able  to  elude  their 
pursuers,  are  often  adorned  with  vivid  colours, 
whilst  those  which  are  incapable  of  locomotion, 
escape  the  notice  of  their  enemies  by  resembling 
in  colour  the  stones  and  weeds  which  surround 
them.  Now  tell  me  the  two  principles  /which 
are  to  be  traced  throughout  the  works  of  the 
Creator. 

Child.  The  economy  of  God  and  his  com- 
pensatory providence. 

Teacher.  Bear  these  principles  in  mind,  and 
you  will  see  many  illustrations  of  them  in  the 
habits  of  the  mollusca.  The  following  lines  of 
Pope  will  help  to  fix  them  in  your  memories : 

Nature  to  these,  without  prof  usion,  kind, 
To  proper  organs,  proper  powers  assigned ; 
'  Each  seeming  want '  compensated  of  course, 
Here  with  degrees  of  swiftness,  there  of  force 


LESSON  VII. 

Teacher.     Which  do  you  think  will  be  our 
next  step  in  the  study  of  shells  ? 


44  LESSON  VII. 

Child.  To  learn  the  names  of  shells,  and 
how  to  class  them. 

Teacher.  What  do  you  suppose  first  led 
people  to  adopt  a  classification  ? 

Child.     The  wish  to  arrange  their  shells. 

Teacher.  Yes,  this  would  be  one  inducement, 
but  there  are  many  more  important  advantages 
of  classification.  Suppose  that  you  had  found  a 
variety  of  shells  on  the  sea-shore,  and  wished  to 
inform  a  friend  of  the  specimens  you  had  picked 
up,  without  entering  into  a  long  description  of 
each,  what  would  you  do  ? 

Child.    1  would  tell  him  their  names. 

Teacher.  But  if  he  had  never  seen  the  shells 
before!,  what  idea  would  the  name  convey  to 
him  1  If  I  told  you  that  I  had  a  murex  in  my 
hand,  what  notion  would  you  form  of  this  shell] 

Child.  None  at  all  unless  you  showed  it  to 
me. 

Teacher.  But  if  you  had  seen  the  shell, 
observed  its  peculiar  form  and  appearance,  and 
been  told  that  it  was  called  a  murex,  what  would 
then  be  the  effect  of  my  telling  you  that  I  had  a 
murex  in  my  hand  ? 

Child.  I  should  know  exactly  what  kind  of 
shell  you  meant. 

Teacher.  This  will  give  you  some  idea  of  the 
advantages  of  scientific  classification.  In  the 
various  branches  of  natural  history,  those  ob- 
jects which  resemble  each  other  in  essential 
characters  are  formed  into  a  class  or  genus  :  a 
description  of  their  points  of  resemblance  is 
drawn  up,  and  a  name  affixed  to  the  class.  • 


SHELLS.  45 

When  we  have  studied  these  characteristics,  the 
name  will  recall  to  our  minds  the  idea  of  the  set 
of  things  signified  by  it. 

Child.     A  name  then  becomes  very  useful. 

Teacher.     How  does  it  become  so  useful  1 

Child.  By  recalling  to  the  mind  the  things 
which  it  signifies. 

Teacher.  What  is  the  class  of  objects  which 
you  are  about  to  study? 

Child.     Shells. 

Teacher.  In  learning  the  names  of  shells, 
you  will  learn  also  what  the  names  imply.  The 
science  which  treats  of  shells  is  called  Concho- 
logy,  from  the  Greek  words  KOVXV  (conch£)  a  shell, 
and  Xoyo?  (logos)  a  discourse.  From  whence 
does  the  shell  derive  its  shape  and  colour? 

Child.    From  the  animal  that  inhabits  it. 

Teacher.  What  then  do  you  think  that  we 
ought  to  study  as  well  as  the  shell  ? 

Child.     The  mollusca. 

Teacher.  Yes.  But  as  we  are  not  able  to 
procure  many  of  these  animals,  we  cannot  pursue 
that  branch  of  the  science ;  and  we  will  therefore 
follow  the  classification  of  Linnaeus,  which  is 
founded  on  the  shells.  He  first  divides  shells 
into  three  great  classes.  Here  are  a  number  of 
shells.  I  will  arrange  them  in  three  divisions, 
and  you  must  examine  each  set,  and  observe  in 
what  respect  the  shells  they  contain  resemble 
each  other. 

Child.  The  shells  in  one  set  are  formed  of 
one  piece,  in  the  other  of  two  pieces,  and  these 
seem  to  have  several  pieces. 


46  LESSON  VII. 

Teacher.  These  distinct  pieces  are  called 
valves.  Where  have  you  ever  heard  of  a  valve  ? 

Child.  A  pump  has  a  valve, — and  steam 
engines  have  valves. 

Teacher.  Can  you  tell  me  what  is  the  use  of 
the  valve  of  a  pump  ? 

Child.  To  prevent  the  water  from  returning 
into  the  pipe  through  which  it  has  passed. 

Teacher.  The  animals  of  these  shells  with 
two  valves  use  these  pieces  for  a  very  similar 
purpose, — to  exclude  the  water.  Now  that  you 
have  found  out  the  distinguishing  character  of 
these  classes,  I  will  give  you  their  names.. 
Those  shells  which  are  composed  of  only  one 
valve  are  called  univalves,  from  the  Latin,  un  us, 
one,  and  valve.  Shells  composed  of  two  valves 
are  called  bivalves,  from  bis,  the  Latin  for  twice, 
and  valve.  Shells  composed  of  more  than  two 
valves  are  called  multivalves,  from  multws,  the 
Latin  for  many,  and  valve. 


QUESTIONS  ON  THE  MOLLUSCA 
AND  THE  SHELL. 

Questions  will  be  given  at  each  division  of  the  subject,  which 
the  children  should  be  able  to  answer  well  without  assistance, 
before  they  proceed  to  a  new  part. 

1.  Describe  the  animals  called  mollusca. 

2.  Which  of  the    different   senses  do  they 
possess  1 

3.  By  what  means  do  they  advance  on  land  ? 

4.  By  what  means  do  they  advance  in  the  sea? 


SHELLS.  47 

5.  Describe  the  different  methods  by  which 
they  render  themselves  stationary. 

6.  Describe  the  organs  by  which  they  feed 
themselves. 

7.  Name  the  two    classes  into  which   the 
mollusca  are  divided. 

8.  Describe  how  the  animals  of  these  two 
classes  differ  from  each  other. 

9.  Of  what  substances  are  the  shells  formed? 

10.  How  are  they  coloured  ?  and  what  is, sup- 
posed to  occasion  the  regularity  in  the  markings  ? 

11.  How  is  the  form  of  the  shell  regulated? 

12.  What  is  there  remarkable  in  the  formation 
of  shells? 

13.  How  are  shells  fitted  for  the  different 
situations  they  ©ccupy  ? 

14.  How  is  the  compensatory  providence  of 
God  manifested  in  the  history  of  the  mollusca  ? 

15.  Into  how  many  classes  are  shells  divided? 

16.  How  are  the  shells  of  each  class  distin- 
guished ? 

17.  Give  the  derivation  of  the  names  of  the 
classes. 


LESSON  VIIL 
PARTS  OF  AN  UNIVALVE  SHELL. 

Teacher.     To  what  class  do  all  these  shells 
belong  ?* 

*  A  variety  of  univalve  shells  should  be  placed  before  the  party 


48  LESSON  VIII. 

Child.     To  the  class  of  univalve  shells. 

Teacher.  I  intend  that  you  shall  study  the 
univalve  shells  first,  because  they  are  the  most 
simple,  and  their  distinguishing  characters  well 
marked ;  but  before  you  can  describe  these 
shells,  you  must  be  well  acquainted  with  their 
parts.  Here  are  some  univalve  shells, — examine 
them  carefully ;  I  will  give  you  the  names  for 
the  parts,  as  you  discover  them.  First,  consider 
which  appear  to  be  the  principal  parts. 

Child.  These  shells  have  two  principal  parts, 
this  which  swells  out,  and  this  which  is  tapering. 

Teacher.  The  swelling  part  is  called  the 
body,*  and  this  which  is  tapering,  the  spire. 
Observe  how  the  spire  is  produced. 

Child.  It  seems  formed  by  the  rolling  round 
of  a  part  of  the  shell. 

Teacher.  These  parts  that  roll  round  are 
called  whorls,  from  an  old  Saxon  word  signifying 
a  round.  What  do  you  remark  in  these  whorls'? 

Child.  That  they  gradually  increase  in  size. 

Teacher.  Yes  ;  and  as  they  successively  roll 
one  round  another,  what  difference  is  there  in  the 
circles  they  describe  ? 

Child.    They  gradually  increase  in  diameter. 

Teacher.  It  is  from  this  circumstance  that 
the  set  of  whorls  is  called  the  spire,  a  word  de- 
rived from  the  Greek  root  <nr«p,  (speir,)  which 
signifies  convolutions  gradually  increasing  in 
diameter,  just  as  would  be  the  case  in  a  rope 
coiled  up.  In  the  coiled  rope  you  have  the  cir- 

•  See  Plate  L 


SHELLS.  49 

cles  rolled  one  within  the  other,  and  lying  flat,  or 
being  in  the  same  plane.  But  if  the  centre 
whorl  is  gradually  raised  above  the  rest,  what 
form  do  you  obtain  1 

Child.     A  conical  form. 

Teacher.  Do  you  now  perceive  how  the  term 
*pire,  originally  derived  from  a  word  that  sig- 
nifies a  set  of  whorls  gradually  increasing  in 
diameter,  can  be  applied  to  a  conical  form  ? 

Child.  Yes  ;  because  when  the  whorls  rise 
one  above  another,  they  produce  the  conical 
form. 

Teacher.  You  will  find  the  whorls  in  shells 
arranged  in  each  of  the  ways  described.  When 
the  whorls  are  all  upon  the  same  plane,  or  nearly 
so,  the  spire  is  said  to  be  retuse,  a  word  derived 
from  the  Latin,  r#,  back,  and  tusws,  beaten.  Tell 
me  why  this  term  is  chosen,  and  pick  out  some 
shells  with  retuse  spires. 

Child.  I  should  think  this  spire  is  called  re- 
tuse, because  the  whorls  appear  beaten  back  into 
the  body. 

Teacher.  Exactly  so  ;  now  look  at  some 
specimens  that  form  quite  a  contrast  to  these 
retuse  spires. 

Child.  Here  are  some  in  which  the  whorls 
gradually  taper  to  a  very  fine  point ;  what  kind 
of  spire  is  this  ? 

Teacher.  This  very  pointed  spire  is  said  to 
be  subulate,  from  the  Latin  subula,  a  pointed  tool. 
The  term  spire  is  now  employed  to  any  form  re- 
sembling that  produced  by  whorls,  which  gra- 
dually rise  and  decrease,  though  it  be  not  oc 
5 


50  LESSON    VIII. 

casioned  by  whorls.  You  can,  perhaps,  recol- 
lect an  instance  in  architecture,  in  which  the 
name  is  so  applied. 

Child.    Yes,  the  spire  of  a  church. 

Teacher.  When  the  spire  of  a  shell  is  formed 
by  whorls,  which  is  generally  the  case,  it  is  said 
to  be  spirally  convoluted  ;  the  latter  term  is  de- 
rived from  the  Latin  words,  con  together,  and 
volutus  rolled.  Now  examine  the  spire  still 
more  attentively,  and  you  will  find  some  other 
parts. 

Child.  There  is  a  line  formed  where  the 
whorls  meet ;  has  this  line  any  particular  name  1 

Teacher.  Yes,  it  is  called  the  suttvre,  from  the 
Latin  sutura,  a  seam  or  joining  ;  do  you  perceive 
any  difference  in  the  sutures  ? 

Child.  Yes,  in  some  shells  itis  quite  a  ridge, 
and  in  others  it  is  more  like  a  channel. 

Teacher.  When  it  is  raised  like  a  ridge  or 
keel,  it  is  called  carinate,  from  the  Latin  carina, 
a  keel ;  when  it  is  a  sunken  line,  it  is  said  to  be 
channelled.  Now  look  at  your  shells  again. 

Child.  Are  any  parts  of  the  shells  considered 
to  be  the  top  and  bottom. 

Teacher.  Yes,  the  point  of  the  spire  is  the 
top.  You  recollect  what  the  top  and  bottom  of  a 
cone  are  called,  and  you  may  apply  these  terms 
to  shells. 

Child.  The  point  of  the  spire  is  then  the 
apex,  and  the  part  immediately  opposite,  the 
base. 

Teacher.     You  are  right. 

Child.    I  think  that  when  you  described  to  us 


SHELLS.  51 

how  the  shells  were  enlarged,  you  called  the 
opening  the  mouth.  * 

Teacher.  Yes,  it  is  termed  cither  the  mouth 
or  aperture. 

Child.     Shells  have  also  sides. 

Teacher.  Yes,  and  it  is  necessary  that  you 
learn  to  distinguish  the  two  sides.  You  are  sup- 
posed, when  you  describe  a  shell,  to  place  it 
upon  its  base  with  it  mouth  turned  towards  you ; 
the  right  side  will  then  be  that  nearest  to  your 
right  hand,  and  the  left  that  nearest  your  left 
hand. 

Child*  What  is  the  part  turned  toward  me 
called  1 

Teacher.  The  front ;  and  what  do  you  sup- 
pose the  reverse  is  1 

Child.    The  back. 

Teacher.    Look  at  this  section  of  a  shell. 

Child.  Is  it  cut  down  the  middle  that  we  may 
observe  the  inside  1 

Teacher.     Yes  ;  and  what  do  you  perceive  ? 

Child.  There  is  a  pillar  round  which  the 
whorls  appear  to  wind. 

Teacher.  This  pillar  is  called  the  Colwnella, 
from  the  latin  colum  e//a,  a  little  column. 

Child.    Have  we  now  mentioned  all  the  parts? 

Teacher.  No,  you  must  examine  your  shells 
more  attentively. 

Child.     The  edges  of  the  mouth. 

Teacher,  By  what  name  are  the  edges  or 
borders  of  our  mouths  called  ? 

Child.  Lip.  Is  the  same  term  applied  to  the 
edges  of  the  mouth  of  shells  ? 


52  LESSON   VIII. 

Teacher.  Yes,  and  you  must  distinguish 
these  two  lips.  What  is  their  position  ? 

Child.     One  is  on  the  outside  of  the  mouth. 

Teacher.  That  is  called  the  outer  lip  ;  and 
where  is  the  other. 

Child.     Upon  the  body  whorl. 

Teacher.    To  what  part  of  the  shell  is  it  near  ? 

Child.     It  is  near  to  the  columella. 

Teacher.  Yes,  and  it  is  thence  called  the 
columellar  lip.  In  what  respect  do  these  lips 
resemble  ours  ? 

Child.     They  are  the  borders  of  the  mouth. 

Teacher.  Right.  But  how  do  they  differ 
from  our  lips  ? 

Child.     They  are  not  moveable. 

Teacher.  Do  you  suppose  this  is  any  disad- 
vantage to  the  animal. 

Child.  Certainly,  for  he  cannot  close  his  mouth, 
and  so  exclude  the  water  or  keep  out  enemies. 

Teacher.  True,  but  those  species  which 
would  suffer  from  such  an  exposure,  are  pro- 
vided with  a  kind  of  lid  which  fits  into  the  mouth 
and  closes  the  entrance  to  the  shell,  when  the 
animal  retires  within  it.  This  lid  is  called  the 
operculum,  a  Latin  word,  signifying  a  covering. 
The  shells  which  are  furnished  with  this  appen- 
dage are  said  to  be  operculated.  Did  you  ever 
observe  any  thing  at  all  like  it  in  the  snails  ? 

Child.  The  entrance  to  the  shell  is  guarded 
by  a  thin  covering  during  the  winter. 

Teacher.  The  animals  belonging  to  land 
shells,  as  for  instance  snails,  protect  themselves 
from  the  inclemency  of  winter,  by  forming  a  tern 


SHELLS.  53 

porary  covering,  which  adheres  to  the  sides  of 
the  shell,  and  is  deciduous, — that  is,  falling  after 
a  certain  period,  from  Latin  decido,  I  fall.  The 
operculum  of  the  marine  shell  is  of  a  very  differ- 
ent nature.  It  is  either  a  calcareous  or  horny 
substance,  permanent,  and  not  attached  to  the 
shell,  but  to  the  foot  of  the  animal,  who  draws  it 
over  the  mouth  when  he  recedes  into  his  abode. 
Now  tell  me  the  position  of  the  mouth. 

Child.     It  is  on  the  right  side  of  the  shell. 

Teacher.  Observe  whether  that  is  invariably 
its  place. 

Child.  No,  here  is  one  shell  in  which  it  is  on 
the  left  side. 

Teacher.  This  is  the  case  in  some  few  species, 
and  the  shell  is  then  said  to  be  sinistral,  a  word 
derived  from  the  Latin  sinistra,  the  left  hand. 
The  others  are  called  dcxtral  shells,  from  dextra, 
the  Latin  for  the  right  hand.  The  sinistral 
shells  are  also  said  to  be  reversed,  because  the 
whorls  proceed  in  a  direction  contrary  to  their 
usual  course.  Now  look  at  this  very  singular 
shell.  (Murex  haustellum.) 

Child.    It  has  a  long  tube. 

Teacher.     From  what  part  does  it  proceed  ? 

Child.     From  the  mouth. 

Teacher.  Do  you  recollect  any  animals  that 
have  a  somewhat  similar  projection  proceeding 
from  their  rnouths  ] 

Child.  Oh  yes  ;  birds — their  beaks  are  like 
this  part  of  the  shell. 

Teacher.      This  projection  in  shells  is  also 
called  a  beak,  or  rostrum,  the  Latin  for  beak. 
5* 


54  LESSON   VIII. 

Child,     The  beak  is  hollow. 

Teacher.  It  is;  the  interior  is  called  the 
canal,  and  the  shells  which  have  these  beaks  are 
said  to  be  canaliculaied ;  and  when  the  aperture 
has  not  a  beak  or  canal,  it  is  called  entire. 

Child.     Is  the  beak  of  any  use  ? 

Teacher.  Yes,  the  animals  which  have  this 
beak  have  an  elongated  tube,  which  is  in  some 
way  connected  with  their  breathing. 

Child.  Many  of  the  shells  have  projections, 
some  like  thorns,  some  ridges,  and  some  rounded 
protuberances. 

Teacher.  The  projections  resembling  thorns 
are  called  spines,  and  the  shells  which  have  them 
are  said  to  be  spinous.  The  rounded  projec- 
tions are  termed  tubercles,  and  the  shells  on 
which  they  appear  are  called  tuberculous.  The 
ribs,  which  are  longitudinal  rounded  sutures 
formed  at  the  various  growths  of  the  shell,  are 
called  varices,  from  the  Latin  varix,  a  swollen 
vein.  But  such  parts  as  occur  only  in  a  few 
species  we  will  notice  when  we  examine  the 
species.  You  must  now  repeat  to  me  the  parts 
of  a  univalve  shell,  and  I  will  write  them  on  the 
slate. 

Parts  of  a  univalve  shell. 

The  spire.  The  base, 
whorls.  aperture, 

body  whorl.  lips, 

first  whorl.  columellar  lip. 

suture.  outer  lip. 

apex,  columella. 


SHELLS.  55 

The  body.  The  right  side. 

back.  left  side, 

front.  operculum. 

Teacher.  Describe  to  me  each  part  and  its 
position. 

Child.  The  spire  is  composed  of  the  upper 
whorls,  and  is  situated  at  the  upper  part  of  the 
shell. 

The  whorls  are  the  parts  that  roll  round  and 
form  the  spire. 

The  first  whorl  is  the  smallest  whorl,  and  is 
at  the  top  of  the  spire. 

The  body  whorl  is  the  largest  whorl,  and  is  at 
the  base  of  the  shell. 

The  suture  is  the  seam  formed  by  the  meeting 
of  the  whorls. 

The  apex  is  the  top  of  the  spire. 

The  base  is  the  opposite  extremity  to  the  apex, 
and  is  situated  either  at  the  lowest  part  of  the 
aperture,  or  at  the  end  of  the  beak,  when  the 
shell  is  canaliculated. 

The  aperture,  or  mouth,  is  the  entrance  to  the 
cavity  of  the  shell. 

The  lips  are  the  edges  of  the  mouth. 

The  columellar  lip  is  the  lip  nearest  the  colu- 
nella. 

The  outer  lip  is  the  outer  edge  of  the  mouth. 

The  columella  is  the  pillar  round  which  the 
fvhorls  form  their  spiral  volutions. 

The  front  is  that  part  of  the  shell  in  which 
the  mouth  is  situated. 

The  back  is  opposite  to  the  front. 

The  right  side  is  that  part  of  the  shell  which 


56  LESSON  VHI. 

would  be  next  to  the  right  hand  of  a  person 
looking  at  it,  the  front  of  the  shell  being  placed 
opposite  to  him. 

The  left  side  is  that  part  of  the  shell  which 
would  be  next  to  the  left  hand  of  the  person 
looking  at  it,  the  front  being  opposite  to  him. 

Teacher.  Give  me  the  derivation  and  appli- 
cation of  the  word  spire. 

Mention  the  different  kinds  of  spires,  with  the 
derivation  of  the  terms  which  you  use. 

Whence  is  the  term  suture  derived? 

How  do  the  sutures  vary  ? 

What  different  projections  occur  on  the  sur 
faces  of  shells'? 

From  what  is  the  term  varices  derived? 

How  are  the  cavities  of  the  shells  often  closed  ? 

Tell  me  the  derivation  of  the  word  operculum. 

What  different  kinds  of  opercula  are  there? 

What  are  the  shells  called  which  have  a  beak? 

What  is  the  mouth  said  tabe  when  it  has  no 
beak?* 

*  These  model  lessons  have  been  drawn  out. with  so  much 
minuteness  in  order  to  exhibit  two  pri«ciples,  very  important  to  be 
applied  in  this  kind  of  instruction.  1st.  That  the  object  itself  should 
be  presented  to  the  class ;  that  their  powers  of  observation  should 
be  stimulated  and  directed  by  appropriate  questions ;  and  thus  a 
considerable  portion  of  their  knowledge  should  be  acquired  by  them- 
selves, instead  of  all  being  simply  communicated  by.  the  teacher. 
2d  That  whatever  supplementary  information  is  given  should  be 
reproduced  by  the  children  before  the  conclusion  of  the  Jesson. 


CONUS — CONE.  57 

LESSON  IX. 
GENUS.  — CONUS. 

THE  party  should  have  before  them  a  variety 
of  univalve  shells,  among  which  there  should 
be  a  large  proportion  of  such  cones  as  have  the 
characteristics  of  the  genus  well  defined.* 

Teacher.  I  have  brought  a  variety  of  shells 
for  you  to  examine ;  what  is  the  point  of  resem- 
blance which  unites  them  all  in  one  class  ? 

Child.  They  are  all  composed  of  one  valve ; 
they  are  all  univalves. 

Teacher.  From  these  univalve  shells  select 
those  which  appear  to  you  to  be  similar  in  their 
general  appearance,  and  in  the  form  of  their 
mouths. 

Child.     We  have  done  so. 

Teacher.     Explain  to  me  what  you  have  done. 

Child.  We  have  selected  those  shells  which 
have  the  same  general  appearance,  and  a  similar 
kind  of  mouth. 

Teacher.  What  was  the  common  point  of 
resemblance  in  all  the  shells  which  I  have  set 
before  you? 

Child.  Their  being  composed  of  only  one 
valve. 

*  It  is  very  important  in  teaching  children  to  draw  out  the  generic 
character  of  shells,  to  set  before  them  specimens  in  which  the  dis- 
tinguishing features  are  strongly  and  clearly  marked  ;  their  ideas 
will  then  be  distinct,  vivid,  and  permanent.  After  this  they  may 
proceed  to  the  examination  of  shells,  which,  combining  the  qualities 
ol  different  genera,  form  the  connecting  links  between  them. 


58  LESSON  IX. 

Teacher.  And  what  are  the  points  of  dis- 
similarity, that  lead  you  to  separate  the  smaller 
set  from  the  whole  group  ? 

Child.  The  difference  in  their  general  ap- 
pearance, and  in  their  mouth. 

Teacher.  You  have  now  formed  a  smaller 
class.  Such  a  subdivision  is  called  a  genus, 
from  the  Latin  word  gen  us,  a  kind  ;  the  plural 
of  genus  is  genera.  The  characteristic  dis- 
tinction of  each  genus  among  the  univalves  is 
founded  on  the  general  appearance  of  the  shells, 
and  the  form  of  their  mouths.  The  specimens 
which  you  have  chosen  belong  to  the  genus 
called  Conus.  You  must  now  examine  the 
shells  carefully,  and  try  and  discover  in  what 
respect  they  resemble  each  other;  you  will 
then  be  able  to  describe  their  generic  charac- 
ter, or  mark  those  qualities  possessed  in  com- 
mon by  them  all,  and  which  distinguish  them 
from  all  other  shells.  How  will  you  set  about 
this? 

Child.  We  must  compare  them  together, 
and  put  down  those  qualities  which  they  all 
possess. 

Teacher,  First  consider  their  general  appear- 
ance. 

Child.  Their  shape  is  very  similar;  it  re- 
sembles a  cone. 

Teacher.  Yes,  aud  as  their  form  is  conical, 
they  have  received  their  scientific  name  Conus, 
and  their  common  English  name  Cone. 

Child.  The  name  expresses  very  well  the 
appearance  of  the  genus. 


CONUS — CONE.  59 

Teacher.  It  does  ;  but  which  is  the  broadest 
part  of  a  cone  ? 

Child.     The  base. 

Teacher.  And  is  the  base  the  broadest  part 
of  these  shells  I 

Child.     No ;  quite  the  reverse. 

Teacher.  They  are  therefore  said  to  be  in~ 
versely  conical. 

Child.     The  cones  are  spiral. 

Teacher.     Observe  how  the  spire  is  formed. 

Child.     By  the  whorls. 

Teacher .     And  how  are  the  whorls  arranged  ? 

Child.     They  are  spirally  convoluted. 

Teacher.  Compare  the  spires  of  the  cones 
with  those  of  the  other  shells  before  you,  and  tell 
me  what  you  remark. 

Child.  The  whorls  scarcely  rise  one  above 
the  other. 

Teacher.  You  remember  what  a  spire  is 
called,  when  the  whorls  have  the  appearance  of 
being  pushed  into  the  body  whorl. 

Child.  Such  a  spire  is  called  retuse.  Here 
is  a  cone  in  which  the  upper  whorls  appear  so 
pushed  into  the  body  whorl*  that  the  spire  forms 
almost  a  flat  surface. 

Teacher.  What  then  is  the  character  of  the 
spire  of  the  cones. 

Child.     The  spire  of  the  cones  is  retuse. 

Teacher.  Compare  together  all  the  different 
shells  before  you^  and  you  will  find  that  the 
relative  proportion  of  their  parts  varies  very 
much.  In  some  you  will  perceive  that  the 
mouth  is  particularly  large,  in  others  the  spire* 


60  LESSON  IX 

What  is  the  relative  proportion  of  the  parts  of 
the  cone  ? 

Child.     The  body  whorl  is  very  large,  com 
pared  with  the  other  whorls. 

Teacher.  This  peculiarity  is  expressed  by 
the  term  turbinate,  which  is  derived  from  the 
Latin  word  turbin  is,  of  a  whirlwind. 

Child.  Why  is  this  form  of  a  shell  named 
after  a  whirlwind  1 

Teacher.  Because  the  first  sweep  of  a  whirl- 
wind describes  a  circle  much  larger  than  those 
which  succeed,  when  its  power  is  in  some  degree 
exhausted.  Do  you  not  now  perceive  how 
applicable  the  term  is  to  the  form  you  were 
describing  ? 

Child.  Yes.  The  body  whorl  is  very  large 
in  proportion  to  the  others,  just  as  the  first  sweep 
of  a  whirlwind  is  large,  compared  with  those  that 
succeed  it. 

Teacher.  You  have  now  observed  the  general 
appearance  of  the  conus ;  what  particular  part 
were  you  to  take  into  consideration,  in  order  ta 
draw  out  the  generic  character  ? 

Child.     The  mouth. 

Teacher.  And  what  do  you  observe  in  the 
mouth  of  the  cones  ? 

Child.     It  is  long  and  narrow. 

Teacher.  When  the  mouth  is  very  narrow  in 
proportion  to  its  length,  and  also  of  a  nearly 
equal  breadth  throughout,  it  is  called  linear,  from 
its  having  the  character  of  a  line.  In  considering 
the  parts  of  an  object,  is  it  their  form  only  that 
strikes  your  attention  I 


CONUS CONE.  61 

Child.  No;  we  observe  also  their  position 
and  direction. 

Teacher.  You  remember  the  usual  position 
of  the  aperture.  . 

Child.  It  is  almost  always  dextral,  or  on  the 
right  side  of  the  shell. 

Teacher.  And  as  this  is  its  usual  position,  it 
is  not  noticed  in  the  generic  character ;  indeed, 
the  peculiarity  of  a  sinistral  aperture  never  runs 
through  a  whole  genus  of  shells.  But  what  do 
you  observe  with  regard  to  the  direction  which 
the  mouth  of  the  cone  takes  ? 

Child.  It  is  in  the  direction  of  a  line  passing 
from  the  apex  to  the  base,  that  is  the  length  of 
the  shell. 

Teacher.  And  what  do  you  call  the  direction 
of  a  line  passing  from  the  top  of  a  body  to  its 
base? 

Child.  Longitudinal;  the  aperture  of  the 
cone  is  longitudinal. 

Teacher.  You  recollect  learning  in  a  former 
lesson  the  proper  term  for  shells  with  a  beak, 
and  also  for  those  without  one. 

Child.  Yes,  those  with  beaks  are  called 
canaliculated,  and  those  without  entire.  The 
mouth  of  the  cone  is  entire. 

Teacher.  Yes.  A  litttle  experiment  will  lead 
you  to  detect  another  characteristic  of  this  genus. 
Observe,  I  fill  this  shell  (a  Turbo)  with  water  to 
the  edge  of  the  lips — has  any  of  the  liquid  run 
over? 

Child.  No  ;  the  shell  holds  the  water  like  a 
cup. 

6 


62  LESSON  IX. 

Teacher*  When  this  is  the  case,  the  mouth  is 
said  to  be  contracted.  But  observe  what  is  the 
consequence,  when  I  attempt  to  fill  a  cone  with 
water  yp  to  the  lips. 

Child;  The  water  runs  out  before  it  reaches 
the  lips. 

Teacher.  Examine  where  the  liquid  flows 
out,  and  what  is  the  cause  of  this  difference  in 
the  two  shells^ 

Child.  The  water  flows  out  at  the  base  of 
the  cone.  In  the  other  shell  the  lips  are  united  ; 
in  the  cone  they  are  separated  by  a  small 
channel. 

Teacher.  This  channel  is  called  a  sinus, 
from  the  Latin  sin  us,  a  curved  line.  If  the  two 
lips  be  separated  by  a  sinus,  liquid  poured  in 
overflows  before  it  reaches  the  lips ;  the  aperture 
in  this  case  is  called  effuse,  from  the  Latin  fu- 
sus,  which  signifies  poured  out.  You  have  no 
doubt  heard  the  term  effusion  applied  to  the 
overflowing  of  any  liquid  ;  you  now  know  exactly 
what  such  an  expression  means.  Compare  the 
columella  with  the  corresponding  part  in  these 
shells,  (a  Voluta  and  a  Cypraea.) 

Child*     It  is  smooth. 

Teacher.  Examine  all  your  cones,  and  see 
whether  they  are  all  quite  smooth. 

Child.  No  ;  there  are  stripes  at  the  base  of 
some  of  them. 

Teacher.  These  are  called  strict,  the  Latin 
for  stripes.  Are  they  only  perceptible  to  your 
sight! 

Child.     I  can  feel  them  also. 


CONUS — CONE.  63 

• 

Teacher.  What  kind  of  striae  must  they  be  if 
you  can  perceive  them  by  your  touch  ? 

Child.     They  must  be  raised. 

Teacher.  Yes  ;  they  are  slightly  raised  like 
wrinkles,  on  which  account  they  are  called 
rugose  strice,  from  the  Latin  rug  a,  a  wrinkle. 
What  direction  do  they  take  ? 

Child.     An  oblique  direction. 

Teacher.  The  columellar  lip  is  nevertheless 
called  smooth,  because  it  has  but  trifling  eleva- 
tions. How  would  you  describe  the  columellar 
lip  of  a  cone  ? 

Child.  The  columellar  lip  of  a  cone  is  smooth, 
except  that  it  is  marked  by  a  few  oblique  rugose 
strict. 

Teacher.  Remember  that  the  stripes  are  only 
occasional,  not  invariable.  Do  you  think  that 
any  quality  in  these  shells  has  escaped  your  ob- 
servation ? 

Child.  They  are  all  prettily  marked,  and  have 
a  beautiful  polish. 

Teacher.  True;  but  the  colours  of  shells 
and  the  peculiarities  on  their  surfaces  are  not 
spoken  of  in  the  generic  character  ;  these  form 
the  distinctions  of  the  different  species.  We 
will  now  sum  up  what  has  been  said  respecting 
the  cones,  and  thus  draw  out  their  generic  cha- 
racter. You  must  first  mention  to  which  of  the 
three  great  classes  they  belong ;  next  their  ge- 
neral appearance  ;  and  lastly,  the  form  and  pe- 
culiarities in  the  aperture. 


64  LESSON  X. 

• 

*  GENUS  CONUS. 
CONE. 

Generic  character.  Shell  univalve ;  whorls 
spirally  convoluted,  spire  retuse  ;  form  inversely 
conical,  turbinate  ;  aperture  linear,  longitudinal, 
entire,  effuse  at  the  base ;  columellar  lip  smooth, 
sometimes  marked  at  the  base  with  a  few  oblique 
rugose  striae. 


LESSON  X. 
REMARKS  ON  THE  SHELL  AND  ITS  INHABITANT. 

Teacher.  The  genus  conus  is  very  easily 
known  by  its  conical  form  and  smooth  columel- 
lar lip  ;  these  may  be  considered  its  two  distin- 
guishing characters.  Much  has  not  been  dis- 
covered of  the  history  or  habits  of  the  mollusca 
belonging  to  these  shells.  I  will  relate  to  you 
all  the  facts  that  I  have  been  able  to  collect,  and 
you  must  give  your  undivided  attention  to  what 
I  say,  in  order  that  you  may  afterwards  write 
down  the  account  from  recollection. 

The  animal  inhabiting  the  shells  belonging  to 


*  The  generic  character  should  be  written  on  the  slate  before  the 
children ;  they  should  learn  it-,  and  afterwards  occasionally  re- 
peat it. 


CQNUS — CONE.  65 

the  genus  conus  breathes  by  means  of  gills ;  it 
has  two  tentacula  bearing  eyes,  the  mouth  is  a 
long  proboscis,  and  the  foot  is  furnished  with  an 
operculum,  by  which  it  closes  the  entrance  to 
its  shell.  The  section  of  a  cone  displays  a 
fact  very  interesting,  as  it  illustrates  the  singular 
habit  of  its  inmate ;  it  is,  that  the  concealed 
internal  convolutions  are  of  a  much  thinner 
substance  than  the  external  coating,  and  it  is 
supposed  that  this  difference  is  made  by  the 
animal's  absorbing  some  of  the  calcareous  matter 
of  these  convolutions.  The  end  to  be  answered 
by  this  process  is  probably,  that  the  weight  of 
the  shell  may  be  lessened,  without  diminishing 
the  solidity  and  strength  of  its  bulwarks :  and 
if  so,  it  affords  a  beautiful  instance  of  the 
superintending  providence  of  God,  who,  by  the 
instinct  he  implants,  directs  the  habits  of  the 
animal  kingdom.  The  shells  of  this  genus  are 
remarkable  for  the  regularity  of  their  form,  the 
brilliancy  of  their  colours,  and  the  beautiful  va- 
riety and  distinctness  of  their  markings.  They 
are  usually  covered  with  a  thick  epidermis,* 
which  preserves  the  fine  polish  of  the  surface. 
They  are  all  natives  of  the  ocean,  and  are  taken 
in  the  seas  of  hot  climates,  where  they  live  at  a 
depth  of  about  ten  or  twelve  fathoms.")"  They 
are  never  found  on  our  coasts.  Their  name  is 
derived  from  the  Greek,  KUVOS  (conos)  a  cone. 
Now  attend  and  answer  the  questions  I  shall 

*  Epidermis,  an  outer  skin,  from  the  Greek  $j«,  (epi)  upon,  and 
ieppa  (derma)  a  skin, 
f  A  fathom  is  six  feet. 

6* 


66  LESSON   X. 

put  to  you  upon  all  that  I  have  detailed.     What 
kind  of  animal  inhabits  the  cone  1 

Child.  It  is  one  that  breathes  by  means  of 
gills ;  has  a  pair  of  tentacula  bearing  eyes ;  and 
its  mouth  is  a  long  proboscis. 

Teacher.  There  is  one  part  of  the  animal 
which  you  have  not  noticed. 

Child.  It  has  an  operculum  attached  to  its 
foot,  with  which  it  closes  the  aperture  of  its 
shell. 

Teacher.  What  is  remarkable  in  the  habits  of 
these  mollusca  ? 

Child.  They  are  supposed  to  absorb  the 
matter  of  which  the  interior  convolutions  of  their 
shells  are  composed. 

Teacher.  What  then  is  the  appearance  of  the 
shells  when  cut  in  halves  1 

Child.  The  interior  parts  of  the  whorls  are 
thin,  while  the  outer  parts  of  the  shell  are  com- 
paratively thick  and  strong. 

Teacher.  What  advantage  is  the  animal  sup- 
posed to  derive  from  the  different  degrees  of 
thickness  in  the  external  and  internal  convolu- 
tions? 

Child.  The  thinness  of  the  interior  diminishes 
the  weight,  while  the  thickness  of  the  exterior 
preserves  its  strength. 

-•  Teacher.     What  is  there  remarkable  in  the 
external  appearance  of  these  shells  1 

Child.  They  are  remarkable  for  the  regu- 
larity of  their  form,  the  brightness  of  their 
colours,  and  the  variety  and  beauty  of  their  mark- 
ings. 


CONUS — CONE.  67 

Teacher.  What  is  their  appearance  when 
first  taken  out  of  the  ocean  1 

Child.  They  are  generally  covered  with  an 
epidermis,  which  preserves  their  beautiful  polish 

Teacher.     To  what  seas  do  they  belong  ? 

Child.     To  the  seas  of  warm  climates. 

Teacher.  And  what  is  their  situation  in  the 
ocean  1 

Child.  About  ten  or  twelve  fathoms  under 
water.  How  much  is  a  fathom  ? 

Teacher.  A  fathom  is  six  feet ;  how  many 
feet  are  they  under  water  ? 

Child.    Between  sixty  and  seventy  feet. 

Teacher.  From  what  is  the  name  Conus 
derived  ? 

Child.  The  name  conus  is  derived  from  the 
Greek  KMOS  (conos)  a  cone. 

The  Teacher  should  again  read  to  the  class  the  facts  connected 
with  the  natural  history  of  the  genus,  and  require  them  to  give  an 
account  in  writing  of  all  they  have  heard.  That  they  may  not  be 
discouraged  in  the  outset,  some  assistance  may  at  first  be  given  ; 
but  that  should  be  gradually  removed,  and  the  attention  brought  into 


composition,  is  nuency,  ana  tnis  win  oe  oest  promotea  oy  anow- 
ing  them  to  use  their  own  expressions,  and  follow  their  own  ar- 
rangement of  the  subject.  When  they  have  learned  to  express 
themselves  readily,  they  should  be  taught  to  seek  for  correct  and 
appropriate  language,  and  themselves  to  correct  the  inaccuracies 
and  inelegancies  frequent  in  the  compositions  of  children.  They 
should  also  be  instructed  to  consider  their  subject  well,  before  they 
begin  to  write  on  it,  that  they  may  arrange  the  matter  in  the  best 
order. 


68  LESSON   XI. 


LESSON  XL 

Teacher.  If  any  one  were  now  to  speak  to 
you  of  a  Conus,  what  idea  would  the  name  call 
up  to  your  mind] 

Child.  The  name  Conus  would  recall  the 
idea  of  a  univalve  shell,  whose  form  is  inversely 
conical  and  turbinate  ;  the  spire  retuse  ;  whorls 
spirally  convoluted,  aperture  linear,  longitudinal, 
entire,  effuse  at  the  base ;  its  columellar  lip 
smooth,  having  sometimes  a  few  oblique  rugose 
striaB  towards  its  base. 

Teacher.  Yes,  all  the  shells  before  us  pos- 
sess these  qualities,  or  they  would  not  be 
Cones  :— -but  are  they  alike  in  all  respects  ? 

Child.  No  ;  they  differ  very  much  in  their 
colours  and  patterns,  and  also  in  their  size. 

Teacher.  On  account  of  this  variety  in  the 
shells  possessing  the  same  generic  marks,  the 
different  genera  have  been  subdivide^  into  spe- 
cies, the  characters  of  which  are  determined  by 
the  circumstances  of  colour,  markings,  size,  and 
the  inequalities  of  the  surface.  Here  is  a  shell 
called  Conus  marmoreus :  I  wish  you  to  examine 
it,  and  draw  out  its  specific  character ;  it  is  con- 
sidered as  the  type  or  representative  of  the  Co- 
nus, from  its  having  the  characteristics  of  the 
genus  strongly  marked.  Now,  tell  me  what  you 
have  to  do. 

Child.    We  must  try  and  describe  this  shell. 

Teacher,  Yes  ;  but  you  must  recollect  that 
they  are  the  specific  distinctions  only,  that  yoa 


CONUS — CONE.  69 

are  to  point  out ;  you  must  now  omit  the  generic 
marks,  as  you  have  already  determined  them, 
and  they  are  implied  in  the  name  Conus.  First, 
what  is  the  size  of  this  Cone?* 

Child.  It  is  rather  more  than  two  inches  long. 

Teacher.  Yes,  in  length  it  generally  varies 
from  two  to  three  inches.  What  is  the  colour 
of  the  shell,  and  that  of  its  markings  ? 

Child.  The  ground  is  a  dark  chestnut  brown, 
approaching  to  black,  and  the  markings  are 
white. 

Teacher.  What  form  do  the  spots  most  nearly 
resemble  ? 

Child.     They  are  nearly  triangular. 

Teacher.  You  may  denominate  them  white 
subtriangular  spots  ;  sub  means  under,  and  when 
prefixed  to  an  adjective,  implies  that  the  quality 
spoken  of  exists  in  the  object  in  an  inferior  de- 
gree. Examine  the  substance  of  the  shell. 

Child.     It  is  heavy  and  thick. 

Teacher.  It  is  a  ponderous  shell ;  now  look 
at  the  spire,  and  tell  me  what  you  remark  in  it. 

Child.  It  has  little  swellings  placed  regularly 
at  the  edges  of  the  whorls. 

Teacher.  These  swellings  are  called  tuber- 
cles, and  a  spire  marked  with  such  inequalities 
is  said  to  be  coronated. 

Child.     I  suppose  that  means  crowned. 

*  The  children  should  have  the  length  of  an  inch  given  to  them, 
and  by  degrees  they  will  learn  to  determine  the  dimensions  of  the 
specimens  without  measuring  them.  They  should  also  be  prac- 
tised in  deciding  colours  and  their  various  shades,  by  referring  at 
first  to  some  standard.  Werner's  Nomenclature  of  colours  is  a  use- 
ful  work  for  this  purpose. 


70  LESSON    XI. 

Teacher,  Yes,  the  spire  is  so  called  from  its 
crown-like  appearance  :  do  you  observe  any 
other  peculiarity  in  it  ? 

Child.  The  whorls  are  concave ;  and  in  most 
shells  they  are  convex. 

Teacher.  The  whorls  in  this  shell  form  a 
little  spiral  channel,  and  are  thence  said  to  be 
channelled.  We  will  now  write  down  the  spe- 
cific character  ;  but  I  must  inform  you,  that  the 
name  marmoreus  is  derived  from  the  Latin  mar- 
wior,  marble ;  and  is  applied  to  these  shells  on 
account  pf  their  mottled  appearance. 


CONUS  Marmoreus* 
MARBLED    CONE. 

Specific  character.  Shell  ponderous,  smooth, 
dark  chestnut  brown,  with  white  sub  triangular 
spots  ;  spire  coronated,  whorls  concave  ;  size, 
from  twp  to  three  inches  in  length. 

*  Plate  II.  fig.  1. 


CYPft^A COWRY.  71 

GENUS.— CYPR^A.* 

COWRY. 

Generic  character.^  Shell  univalve,  invo- 
luted,J  smooth;  form,  suboval,  resembling  a 
coffee  berry,  obtuse  at  both  ends  ;  aperture 
linear,  longitudinal,  extending  the  length  of  the 
shell,  effuse  at  each  end  ;  lips  curved  inwards 
and  toothed  ;  the  spire  in  some  species  just  per- 
ceptible, in  others  not  obvious,  but  it*  position 
marked  by  an  umbilicus.  § 

OBSERVATIONS  ON  THE  SHELL  AND'  ITS 
INHABITANT. 

The  Cypraeae,  of  which  there  are  numerous 
species,  display  a  high  natural  polishr  uniformity 
of  shape,  delicate  and  distinct  markings,  with 
great  beauty  and  variety  of  colours.  They  are 
readily  distinguished  from  all  other  shells  by 
their  lips  being  rolled  inwards,  and  both  of  them 
being  toothed.  The  history  of  the  genus  is  very 

•  Plate  II,  fig.  2,  4,  5. 

t  The  proposed  manned  of  imparting  instruction  upon  Natural 
History,  so  as  at  the  same  time  to  develop  the  faculties  of  children, 
having  been  fully  shown  in  the  preceding  pages,  the  substance 
only  of  the  lessons  will  now  be  given  for  the  use  of  the  Teacher, 
who,  it  is  supposed,  will  analyse  it  and  arrange  it  in  questions  ac- 
cording to  the  plan  of  the  foregoing  lessons.  A  frequent  repetition 
of  the  generic  character  is  recommended,  and  also  that  the  chil- 
dren  be.  required  occasionally  to  give  a  list  of  the  parts  of  a  shell, 
and  definitions  of  the  terms  they  use^ 

\  Involuted.  Boiled  inwards,  the  first  whorls  being  rolled  within 
the  body  whorl,  from  the  Latin  invofut  us,  rolled  up  in. 

§  Umbilicus.  A  small  hollow:  this  term  was  appliedby  the 
ancients  to  the  centre  of  the  shield;, 


72  LESSON    XI. 

interesting,  from  the  remarkable  difference  in  the 
appearance  of  the  same  shell  at  the  various  stages 
of  its  growth.  In  its  earliest  state,  the  substance 
of  the  shell  is  ve*ry  thin,  almost  colourless,  and 
dull ;  the  mouth  rather  wide,  the  outer  lip  not 
rolled  inwards,  but  having  a  sharp  edge,  and 
neither  lip  denticulated.  The  shell  which  the 
animal  first  forms  is  so  dissimilar  to  the  perfect 
Cypraea,  that  it  has  been  considered  as  belong- 
ing to  another  genus.  In  the  second,  or  inter- 
mediate period  of  growth,  the  shell  begins  to 
approach  the  general  form  that  characterizes  the 
genus.  The  lips  are  curved  inwards,  and  the 
teeth  become  apparent ;  but  the  substance  is  still 
thin,  the  colour  faint,  and  the  markings  seldom 
more  than  ill-defined  transverse  bands.  In  its 
third  and  perfect  state,  the  Cypraea  has  received 
an  additional  coating  of  testaceous  matter,  the 
pattern  appears  with  its  vivid  tints  and  delicate 
markings,  and  the  spire,  if  not  entirely  hidden, 
yet  scarcely  projects  out  of  the  body  whorl. 
The  animal  itself  undergoes  a  considerable 
change  in  appearance  during  its  growth ;  its 
mantle  at  first  is  small,  but  increases  with  its  age, 
and  expands  at  the  sides  into  two  ample  wings ; 
from  these  is  deposited  the  final  layer  which 
completes  the  shell. 

In  the  adult  specimens,  these  expansions  of 
the  mantle  completely  cover  the  shell,  when  the 
animal  emerges  to  seek  its  food  ;  at  the  place 
where  they  unite,  a  longitudinal  line  is  formed 
on  the  back  of  the  shell,  thence  called  the  dorsal* 

.Dorsal,  belonging  to  the  back,  from  the  Latin'ciorswwi  the  back. 


CYPR^A — COWRY.  73 

line ;  when  the  wings  are  so  large  that  they  fold 
one  over  the  other,  their  place  of  junction  is  not 
marked.  The  external  polish  of  these  shells  is 
owing  to  their  being  covered  continually  by  the 
mantle.  The  animals  inhabiting  the  Cyprsea, 
have  a  fleshy  foot  with  which  they  crawl,  similar 
to  that  of  the  snail ;  the  head  is  placed  on  a 
neck,  and  has  two  finely  pointed  tentacula,  with 
two  eyes  situated  at  their  base :  the  mouth  is  a 
round  opening  armed  with  teeth,  which  act  not 
only  as  organs  of  nutrition,  but  as  defensive 
weapons.  The  mantle  in  front  forms  a  kind  of 
tube,  which  is  lodged  in  the  notch  of  the  shell ; 
through  this  the  mollusca  imbibes  water.  In  a 
state  of  rest  the  Cypraese  remain  buried  under 
the  sea  at  some  distance  from  the  shore,  but  it  is 
said  that  at  full  of  the  moon  they  quit  this  retreat 
and  traverse  the  rocks.  They  belong  principally 
to  the  seas  of  hot  climates  ;  a  few  species  are 
met  with  in  temperate  regions,  but  these  possess 
not  the  beauty  of  colouring  displayed  by  their 
congeners.*  It  may  generally  be  observed  with 
regard  to  shells,  that  the  intensity  of  their  co- 
louring decreases  as  their  locality  approaches 
the  poles.  One  species  called  the  Cypra^a  Mo- 
neta,|  is  the  current  money  of  Bengal,  Siam, 
and  Africa  ;  it  is  picked  up  by  the  negro  women 
of  the  Indian  islands  about  the  full  of  the  moon. 
This  genus,  on  account  of  its  great  beauty,  was 
formerly  dedicated  to  Venus,  the  fabulous  divi- 

*  Congener— one  of  the  same  genus,  from  Latin  con,  together, 
and  gen  us. 
t  Plate  II.  fig.  4. 

9 


74  LESSON   XI. 

nity  of  the  island  of  Cyprus,  from  which  circum- 
stance its  name  is  derived. 

CYPR-33A  Arabica* 
NUTMEG    COWRY. 

Specific  character.  Shell  subovate ;  colour 
brownish,  or  blueish  white,  inscribed  with  dark 
brown  markings  resembling  Arabic  characters  ; 
the  sides  are  thickened  and  spotted  with  purple ; 
the  teeth  are  chestnut  brown  ;  the  dorsal  streak 
is  simple. 

The  shell  is  from  two  to  three  inches  long,  the 
breadth  is  nearly  three  quarters  of  its  length. 

The  young  shells  of  this  species  are  blueish 
gray,  variously  clouded  or  banded  with  brown ; 
when  the  teeth  are  formed,  the  back  appears  of  a 
brownish  or  dull  blue  colour ;  in  this  stage  of  its 
growth,  it  has  been  known  by  the  name  of  Cyprsea 
Amethystea,  or  the  smoke  Cowry.  Linnaeus  was 
not  aware  of  the  variety  in  the  appearance  of 
these  Cowries  at  their  different  periods  of 
growth,  and  from  this  defect  in  his  knowledge, 
he  has  described  the  present  species  under  three 
different  names. 

CYPRSEA  Eurapea.] 
NUN    COWRY. 

Specific  character.  Shell  ovate,  about  half  an 
inch  long,  and  a  quarter  broad,  transversely  rib- 

•  Plate  H.  fig.  3.  f  Plate  11.  fig.  5. 


BULLA DIPPER.  75 

bed,  the  ribs  terminating  within  the  lips  ;  of  a 
pale  purple  or  flesh  colour,  with  three  dark  spots 
on  the  ridge  of  the  back. 

This  is  a  British  species,  and  found  abun- 
dantly on  our  shores ;  it  greatly  resembles  the 
West  Indian  species,  but  is  distinguished  from 
it,  in  having  no  dorsal  groove,  and  the  dorsal 
spots,  if  there  are  any,  being  limited  to  three. 
Both  the  shell  and  the  inhabitant  vary  so  much 
in  their  different  stages  of  growth,  that  much  con- 
fusion has  arisen  in  their  classification.  The 
shell  in  its  juvenile  state  is  extremely  thin, 
brittle,  pellucid,  and  quite  smooth ;  and  the  ani- 
mal of  a  pale  colour,  displaying  no  reflected 
membrane.  In  its  adult  state  the  shell  is  thick, 
opaque,  ribbed,  and  the  animal  extends  over  it 
the  lateral  appendages  of  its  mantle,  which  are 
speckled  with  a  variety  of  colours,  giving  a  beau- 
tiful appearance  to  the  animal  when  in  motion 
under  the  water 

GENUS.— BULLA.* 

DIPPER   OR   WATER   BUBBLE. 

Generic  character.  Shell  univalve,  convo- 
luted, often  without  any  spire,  smooth  ;|  shape 
suboval,  inflated ;  aperture  longitudinal, generally 
the  length  of  the  shell,  entire  at  the  base,  con- 
tracted ;  columella  oblique,  smooth- 

•  Plate  II.  fig.  6,  9,  9. 

fTheBulke  are  said  to  be  smooth,  because  their  surface  has 
never  any  projections. 


76  LESSON  XI. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

This  genus  is  perhaps  less  accurately  defined 
than  any  other  of  the  Linnaean  Genera  :  it  con- 
tains an  assemblage  of  shells  presenting  a  very 
varied  appearance ;  indeed  it  seems  as  if  it  had 
been  formed  to  be  a  receptacle  for  including  all 
the  species  that  could  not  find  a  place  in  other 
genera.  The  most  distinguishing  characteristic 
of  the  Bulla  is  its  gibbous  or  inflated  figure,  to 
which  it  owes  its  name,  signifying  water  bub- 
ble. One  species  (Bulla  Ovum)  bears  a  very 
striking  resemblance  to  the  Cyprsea,  it  differs 
from  that  genus  only  by  the  absence  of  teeth  on 
the  columellar  lip.  Some  of  the  Bullse  are  re- 
markable for  having  both  ends  of  the  mouth  pro- 
duced into  long  beaks  ;  these  shells  are  called 
birostrate.* 

The  inhabitants  of  many  of  the  Bullse  are 
larger  than  their  shells,  so  that  they  cannot  wholly 
recede  into  them ;  indeed  in  many  the  usual 
order  is  reversed,  and  the  shell  is  so  surrounded 
and  enveloped  in  the  body  of  the  animal,  that  no 
part  of  it  is  visible,  and  an  inexperienced  person 
would  little  expect  to  find  a  regular  testaceous 
specimen  buried  in  an  unsightly  slug. 

A  very  remarkable  circumstance  in  the  forma- 
tion of  many  of  the  animals  of  this  genus,  is  that 
they  are  furnished  with  a  gizzard  to  masticate 
and  digest  their  food.  This  organ  is  composed 

*  The  children  being  acquainted  with  the  words  rostrum  and  bis, 
will  see  at  once  the  derivation  of  this  word. 


BULLA DIPPER.  77 

of  two  or  three  plates,  sometimes  of  a  corneous,* 
and  sometimes  of  a  testaceous  nature ;  these 
plates  have  a  roughness  and  prominency  in 
their  centre,  by  which  they  are  fitted  to  grind 
whatever  comes  under  their  action ;  they  are 
surrounded  and  connected  by  a  cartilaginous 
ligament  by  which  they  are  moved.  This  giz- 
zard appears  an  extraordinary  organ  for  such 
an  animal  to  possess,  but  upon  dissecting  these 
mollusca,  small  shells  have  been  frequently 
found  in  their  gizzard,  and  even  the  testaceous 
matter  reduced  to  a  powder,  affording  ample 
proof  that  it  unites  the  two  offices  of  mastication 
and  digestion. 

The  Bullae  are  not  furnished  with  an  oper- 
cuium ;  indeed  to  many  of  the  species  it  would 
be  a  useless  appendage,  as  the  animal  extends 
beyond  the  shell,  and  cannot,  on  account  of  its 
gizzard,  contract  itself  so  as  to  retire  within. 
The  marine  species  also  reside  in  deep  water, 
and  they  are  as  safe  there  from  crabs  and  other 
enemies  as  the  mollusca  who  live  near  the  shore, 
and  barricade  the  mouth  of  their  shells  with  their 
opercula. 

BULLA  LignariaJ 
WOOD  DIPPER. 

Specific  character.  Shell  oval,  thin,  brittle, 
semi-transparent,  yellowish  or  chestnut  brown, 

*  Corneous,  horny,  from  the  Latin  cornu,  a  horn, 
t  Plate  II.  fig.  6. 

7* 


78  LESSON   XI. 

with  numerous  transverse  striae  of  a  light  colour 
approaching  to  white,  and  giving  it  some  resem- 
blance to  veined  wood ;  sometimes  it  has  one  or 
two  oblique  bands  ;  inside  white,  glossy  ;  aper- 
ture large,  extending  the  whole  length  of  the 
shell,  somewhat  contracted  towards  the  upper 
part ;  columellar  lip  smooth  ;  it  has  no  external 
convolutions,  but  at  the  top  is  depressed,  and 
has  a  small  umbilicus ;  it  is  usually  about  two 
inches  long,  and  one  and  a  quarter  broad  at  the 
base. 

This  is  one  of  the  Bull 33  which  possess  a 
gizzard.*  In  this  animal  it  consists  of  two 
triangular,  thin,  testaceous  plates  nearly  an  inch 
in  diameter,  and  another  of  an  elongated  semi- 
cylindrical  form.  These  platos  are  connected 
together  by  a  tough  yellowish  ligament.  Within 
or  near  this  powerful  digestive  organ  have  been 
found  the  smaller  tribe  of  testacea,  and  also  the 
powder  of  their  shells  in  considerable  quantities. 

This  is  the  largest  species   of  the  British 

Bull®. 

BULLA  Fontinalis.] 
STREAM    DIPPER. 

Specific  character.  Shell  sinistral,  having 
four  or  five  reversed  volutions,  glossy,  pellucid,J 
and  of  a  light  horn  colour;  the  body  whorl  is 
large ;  the  others  are  very  small,  and  not  much 

*  Plate  II.  fig.  7.  f  Plate  II.  fig.  9. 

{ Pellucid,  so  clear  that  the  light   is  seen  through   it.    From 
JLaiin,  per  through,  and  lux  light, 


BULLA DIPPPER.  79 

produced ;  aperture  oval  oblong,  three  fourths 
of  the  length  of  the  shell.  Old  specimens  are 
somewhat  striated,  and  rather  wrinkled  longitu- 
dinally, with  two  or  three  faint  transverse  ridges 
on  the  body  whorl.  Length  half  an  inch,  breadth 
a  quarter. 

This  is  a  British  species,  not  unfrequently 
found  in  stagnant  pools  and  running  waters, 
upon  the  under  side  of  the  leaves  of  aquatic 
.plants. 

The  animal  is  of  a  light  yellowish  colour,  has 
two  long  setaceous*  tentacula,  with  two  black 
eyes  placed  underneath  at  their  base.  When  in 
motion,  it  covers  great  part  of  the  shell  with  a 
transparent  membrane,  scarcely  perceptible  to 
the  naked  eye. 

It  has  very  considerable  powers  of  locomotion, 
and  transports  itself  with  the  shell  downwards, 
by  adhering  to  the  surface  of  the  water,  crawling 
over  it  with  as  much  apparent  ease  as  if  on  a 
solid  body.  It  can  also  let  itself  down  gradu- 
ally by  a  thread  affixed  to  the  surface  of  the 
water,  as  a  caterpillar  does  from  the  branch  of  a 
tree ;  it  is  the  only  animal  that  is  known  to  be 
capable  of  thus  suspending  itself  under  water. 
It  has  the  power  of  throwing  its  shell  about  in  an 
extraordinary  manner,  continuing,  at  the  same 
time,  fixed  by  its  foot.  It  resorts  to  this  singular 
habit  either  in  self-defence,  or  to  remove  the 
little  aquatic  animals  with  which  it  is  tormented. 

*  Setaceous— bristle  shaped,  from  Latin  seta,  a  bristle. 


80  LESSON   XI. 

GENUS.— VOLUTA.  * 

VOLUTE  OR  WREATH. 

Generic  character.  Shell  univalve,  spirally 
convoluted,  shape  suboval ;  aperture  narrow, 
longitudinal,  generally  effuse  at  the  base  ;  having 
sometimes  a  dorsal  notch ;  columella'has  oblique 
plaits,  varying  in  size  and  number. 

OBSERVATIONS   ON  THE  SHELL  AND  ITS 
INHABITANT. 

This  genus  contains  shells  highly  valued  for 
their  variety,  the  beauty  of  their  colours,  and  the 
brightness  of  their  natural  polish.  They  vary 
considerably  in  their  appearance.  Some  have 
the  aperture  entire  ;  in  others  it  is  effuse,  termi- 
nated by  a  notch,  or  produced  into  a  canal ;  the 
distinctive  mark  however  by  which  they  may  be 
immediately  recognised  is  the  plicatedf  columel- 
lar  lip.  It  is  supposed  that  the  animals  inhabi- 
ting the  Volutes,  must  differ  materially  as  well  as 
the  shells,  since  the  abode  of  the  mollusca  is  in- 
variably suited  to  their  conformation  and  habits. 
There  are  but  very  few  British  species  of  this 
genus,  and  even  these  are  doubtful. 

The  term  Voluta  signifies  rolled  up  cylindri- 
cally. 

One  large  family  has  been  separated  by  mo- 
dern conchclogists  from  the  Volutes,  and  formed 
into  a  distinct  genus  called  Oliva,  composed 

*  Plate  II.  fig.  10  11.  f  Derived  from  Latin,  plica,  a  fold. 


VOLUTE VOLUTE.  81 

principally  of  the  Voluta  Oliva*  of  Linnaeus. 
These  shells  are  of  a  cylindrical  form,  have  a 
short  spire,  and  the  aperture  notched  at  the  base. 
They  are  easily  distinguished  from  all  other  Vo- 
lutes, by  having  their  whorls  separated  by  a  chan- 
nel. Their  surface  displays  a  fine  polish,  and  many 
of  them  are  beautifully  coloured.  It  appears  that 
the  Olives  are  formed,  like  the  Cowries,  of  two 
coatings  of  testaceous  matter;  when  the  upper 
one  is  artificially  removed,  that  underneath  often 
displays  most  beautiful  tints.  They  are  found 
in  hot  climates.  The  animals  which  inhabit 
them,  breathe  only  water,  which  they  inhale  by 
means  of  a  tube  situated  under  the  head,  and 
fitting  into  the  dorsal  notch. 

Another  large  family  of  Yolutes  are  called 
Mitres,  from  their  resemblance  to  those  insignia 
of  clerical  dignity.  The  shells  of  which  it  is 
constituted  are  now  arranged  in  a  distinct  genus. 
Their  form  is  more  elongated  than  that  of  their 
congeners,  being  turreted  or  fusiform,  and  the 
apex  very  pointed.  They  are  also  character- 
ized by  the  gradual  decrease  in  the  size  of  the 
columellar  fold  as  they  approach  the  base.  These 
shells  are  as  much  admired  for  the  brightness  and 
variety  of  their  colours  as  for  the  elegance  of 
their  form.  They  are  found  in  the  seas  of  hot 
climates.  The  natives  of  the  Island  of  Tama  fix 
them  into  handles  and  use  them  for  hatchets. 
The  Yoluta  Episcopalis  or  Bishop's  Mitre,f  is  the 
type  of  this  family.  It  is  white,  marked  with 
distinct  orange  spots.  It  is  frequently  found  in 

•  Plate  II.  fig.  10.  f  Plate  II.  fig.  11. 


82  LESSON   XI. 

India.  Its  inhabitant  is  said  to  be  of  a  poisonous 
nature,  and  to  wound  with  its  pointed  proboscis 
whoever  ventures  to  touch  it. 


VOLUTA  Musica. 

MUSIC    SHELL. 

Specific  character.  Shell  oval,  with  pointed 
tubercles  on  the  whorls  ;  aperture  emarginate,* 
columella  with  eight  plaits  ;  outer  lip  smooth 
and  thick ;  shell  two  or  three  inches  in  length, 
colour  white  or  buff;  it  is  remarkable  for  its 
dark  markings,  arranged  like  a  stave  in  music, 
in  parallel  lines,  upon  which  are  spots  resem- 
bling the  notes ;  from  this  appearance  it  derives 
its  name. 

VOLUTA  Pyrum. 

TURNIP   VOLUTA. 

Specific  character.  Shell  pear-shaped,  ponde- 
rous, smooth,  canal iculated,  striated,  and  slightly 
nodulous  transversely  ;  spire  acute,  columellar 
lip  with  three  plaits  ;  colour  dirty  white ;  the 
young  shells  are  yellowish,  and  have  irregular 
transverse  rows  of  dark  spots.  The  size  of  the 
perfect  shell  is  about  five  inches  long,  and  about 
half  as  broad. 

•  Ernarginate,  notched,  or  having  the  margin  excavated  by  a 
sinus. 


BUCCINUM WHELK.  83 

The  reversed  shells  of  this  species  are  held 
sacred  in  China,  where  a  great  price  is  given  for 
them  ;  they  are  kept  in  pagodas  by  the  priests, 
who  on  certain  occasions  administer  medicine  to 
the  sick  out  of  them,  and  also  use  them  to  anoint 
the  Emperor  at  his  coronation.  They  are  often 
curiously  ornamented  with  carvings,  executed  by 
the  Indians  who  use  them  for  drinking  cups. 


GENUS.— BUCCINUM.* 


WHELK. 

Generic  character.  Shell  univalve,  spirally 
convoluted,  frequently  canaliculated  ;  from  gib- 
bous ;  aperture  ovate,  effuse  at  the  base,  ending 
in  a  short  canal,  abruptly  curved  and  turning  to 
the  right,  that  is,  from  the  outer  lip ;  columellar 
lip  flattened. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  characters  which  distinguish  this  genus 
do  not  always  occur  in  each  species.  The  most 
invariable  mark  of  distinction  is  the  direction  of 
the  canal ;  and  should  this  fail,  as  is  the  case  in 
a  few  instances,  the  thick  gibbous  form  or  flat- 

*  Plate  III.  fig.  1,  2,  3,  4. 


84  LESSON   XI. 

tened  columella  still  points  out  the  proper  situa 
tion  of  the  shell  to  be  among  the  Buccina. 

One  division  of  this  genus  is  known  by  the 
common  name  of  Tuns.  These  shells  are  thin, 
brittle,  turbinate,  of  an  inflated  or  globular  form* 
transversely  ribbed,  and  have  a  notch  at  the 
base  of  the  aperture.  The  type  is  the  Buc- 
cinum  Dolium.* 

Many  of  the  Buccina  are  called  Helmets, 
and  are  distinguished  by  their  inflated,  turbinate 
form,  and  by  their  short  beak  abruptly  reflected ; 
their  columellar  lip  is  thickened  and  spread  over 
the  body  whorl,  forming  a  flat  expansion  ;  their 
outer  lip  is  also  re  volute,")*  and  often  dentated  ;  J 
their  spire  is  retuse  and  marked  at  intervals  by 
curved  ridges,  which  are  the  permanent  margins 
of  the  former  apertures,  and  are  interesting,  as 
marking  clearly  the  various  stages  of  the  shell's 
increase.  The  Helmets  are  very  common,  and 
many  are  remarkable  on  account  of  their  size 
and  solidity.  One  species  (the  Buccinum  Cor- 
nutum)  is  more  than  a  foot  in  length.  It  is  a 
handsome  shell,  and  often  used  as  an  ornament 
in  rooms.  It  is  found  mostly  in  tropical  seas, 
distant  from  the  shores,  in  sandy  bottoms  where 
the  animal  buries  itself  in  search  of  prey. 

The  most  beautiful  shells  of  this  genus  are 
called  Harps  ;§  they  have  an  elegant  shape,  rich 
tints,  and  usually  a  glossy  surface ;  their  form 
is  oval,  spire  short,  aperture  large,  notched  at  the 

*  Plate  III.  figure  1.  t  Revolute,  rolled  back, 

J  Dentated  :  tooth,  from  Latin,  dens-,  a  tooth. 
$  Plate  HI.  figures. 


BUCCINUM WHELK.  85 

base,  outer  lip  thickened  and  rolled  outwards. 
The  animal  produces  this  thickened  revolute 
lip  at  different  periods  of  its  growth,  thus  form- 
ing a  number  of  elevated  ridges  on  the  shell. 
Such  marks  of  increase  are  observable  in  many 
other  marine  shells,  and  in  a  few  land  species  ; 
but  in  none  do  they  occur  more  frequently  than 
in  the  Harps.  The  effect  of  these  numerous 
ribs  is  very  rich  and  pleasing.  The  Harps  are 
found  in  the  seas  of  hot  climates,  particularly 
near  the  Isle  of  France. 

Another  very  distinct  natural  group  of  this 
genus  consists  of  shells  called  Needle  Bucci- 
num,*  a  term  given  to  them  from  their  subulate 
form.  They  possess  the  characteristic  mark  of 
the  genus  in  the  notch  of  the  aperture  slanting 
towards  the  right,  though  their  pointed  elongated 
shape  has  a  very  different  appearance  from  that 
of  the  Buccina  in  general. 

The  name  given  to  this  genus  is  derived  from 
the  Latin  buccina,  a  trumpet,  and  probably 
these  shells  furnished  the  first  idea  of  that  in- 
strument, for  if  the  apex  be  pierced  or  broken 
off,  a  variety  of  sounds  may  be  produced  by 
blowing  into  it.  Triton,  the  fabled  trumpeter  of 
Neptune,  is  represented  with  one  of  these  shells 
in  his  hand,  when  he  is  supposed  to  be  calling  up 
the  river  deities  to  attend  their  monarch.  This 
kind  of  trumpet  is  still  used  by  the  Italian  herds- 
men to  direct  the  movements  of  their  cattle. 
In  a  part  of  Wales  also  the  fanners  summon 


*  Plate  III.  figure  4. 
8 


86  LESSON  XI. 

their  labourers  in  a  similar  manner,  and  the 
deep  and  sonorous  notes  produced  breaking  in 
upon  the  silence  of  those  mountainous  districts, 
have  a  very  striking  effect.  In  Palestine  the  bee 
masters  enticed  their  bees  with  a  whistle  made 
by  means  of  some  shell,  (probably  a  Buccinum,) 
and  led  them  from  meadow  to  meadow  to  collect 
their  store  of  sweets.  Isaiah  seems  to  refer  to 
this  custom  when  he  prophecies  the  conquests 
of  the  Assyrian  monarch.  "  And  it  shall  come 
to  pass  in  those  days  that  the  Lord  shall  hiss  (or 
whistle)  for  the  bee  that  is  in  the  land  of  Assyria. 
And  they  shall  come,  and  shall  rest  all  of  them 
in  the  desolate  vallies,  and  in  the  holes  of  the 
rock,  and  upon  all  thorns,  and  upon  all  bushes." 
Isa.  vii.  18,  19. 

Various  species  of  turbinated  shells,  chiefly 
of  the  Buccinum  or  Whelk  tribe,  are  picked  up 
on  the  shores  of  the  Isle  of  Wight.  They  are 
not  found  tenanted  by  their  natural  inhabitants, 
who  love  the  deep  recesses  of  the  ocean,  but  by 
a  species  of  Crab  called  the  Bernard,  or  Hermit 
Crab.  .  This  creature  curiously  exhibits  the 
wonderful  operations  of  animal  instinct,  whilst  he 
exemplifies  in  a  striking  manner  the  resources  of 
a  compensatory  Providence.  The  hinder  part 
of  his  body  is  tender  and  naked,  unprotected  by 
that  shelly  covering  which  guards  his  head  and 
anterior  extremities  ;  he  would  therefore  be  pe- 
culiarly liable  to  injuries  were  he  not  endowed 
with  a  foresight  that  directs  him  most  ingeniously 
to  provide  against  any  accident.  This  Crab 
seeks  for  the  roomy  cavity  of  some  forsaken 


BUCCINUM WHELK.  87 

Whelk,  into  which  he  contrives  to  wriggle  him- 
self, maintaining  his  hold  by  means  of  a  hooked 
claw,  which  he  fastens  to  any  projection  in  the 
shell,  while  his  head  and  front  claws  hang  out  at 
the  aperture.  Thus  secure,  he  continues  till 
increased  in  size  he  is  compelled  to  abandon  his 
retreat  and  seek  for  a  tenement  of  more  ample 
dimensions  ;  then  he  may  be  seen  traversing  the 
sands,  searching  with  patience  and  assiduity  for 
another  abode,  and  examining  each  empty 
shell,  till  he  meets  with  one  better  suited  to  his 
wants. 


BUCCINUM  Harpa* 
HARP    SHELL. 

Specific  character.  Shell  oval,  turbinate  with 
longitudinal,  acute,  and  curved  varices  ;  mouth 
expanding,  notched  at  the  base  ;  outer  lip  re- 
volute  ;  columellar  lip  smooth,  flattened ;  va- 
riously marbled  or  banded  with  fawn  colour  or 
reddish  brown ;  size  from  two  to  three  inches 
long,  and  nearly  two-thirds  as  broad. 

There  are  several  varieties  of  this  species, 
which  is  much  distinguished  for  its  beauty. 
They  are  found  principally  in  the  Indian  ocean, 
and  generally  in  the  seas  of  hot  climates.  They 
are  furnished  with  a  horny  operculum. 

*  Plate  III.  figure  2. 


88  LESSON  XI. 

BUCCINUM  Undulatum. 
WAVED   WHELK. 

Specific  character.  Shell  thick  and  coarse, 
with  seven  or  eight  ventricose  whorls,  having 
undulating*  ribs  both  transversely  and  longi- 
tudinally striated  ;  varies  in  colour  from  dirty 
white  to  chestnut  brown ;  size  from  two  to  five 
inches  long,  and  more  than  half  as  broad. 

There  are  scarcely  any  of  our  shores  which 
do  not  produce  this  shell.  It  is  commonly  taken 
in  dredging  by  fishermen,  who  either  use  the 
animal  for  bait,  or  destroy  it.  They  suppose  it 
very  destructive  to  a  large  species  of  scallop  by 
insinuating  its  tail,  as  they  term  the  trunk,  into 
the  shell,  and  killing  the  inhabitant  for  food. 
The  old  shells  are  frequently  covered  with  a 
brown  epidermis,  or  rough  extraneous  matter. 

The  animal  has  two  conical  tentacula  bearing 
eyes  at  their  base,  a  short  foot,  to  which  is 
attached  a  horny  operculum,  and  a  long  trunk 
that  issues  through  the  notch  at  the  base  of  the 
shell. 

BUCCINUM  Lapillus. 
ROCK   WHELK. 

Specific  character.  Shell  ovate,  thick,  with 
five  or  six  whorls  more  or  less  striated  longitu- 

*  Undulating :  wavy,  from  the  Latin  undul  a,  a  small  ware. 


BUCCINUM — WHELK  89 

dinally,  and  transversely  crossed  with  finer  irre- 
gular striae  ;  apex  small,  pointed  ;  aperture  oval ; 
outer  lip  waved  or  denticulated ;  it  is  usually  of 
an  uniform  dirty  white,  or  yellowish  colour, 
sometimes  banded  with  brown  or  yellow.  Length 
rarely  exceeds  two  inches,  breadth  one. 

The  animal  that  inhabits  this  shell  has  two 
slender  tentacula-bearing  eyes  about  half  way 
up  on  the  outside,  the  ends  of  the  tentacula  as  far 
,as  the  eyes  are  retractile*  like  those  of  snails. 
Its  mantle  forms  a  tube  through  which  it  breathes : 
it  has  a  foot  with  a  horny  operculum.  Near  to 
its  head,  and  lying  in  a  little  furrow,  is  a  white 
vein  which  yields  a  beautiful  purple  tint,  sup- 
posed to  be  that  so  long  celebrated  as  the  Tyrian 
rfye.  In  order  to  obtain  this  colour,  the  vein  is 
laid  open  with  a  needle,  and  is  found  to  contain 
a  tenacious  yellow  matter  like  cream.  As  soon 
as  this  fluid  is  put  on  any  substance,  as  silk, 
linen,  &c.  and  exposed  to  the  air,  the  yellow 
assumes  a  brighter  hue,  speedily  turns  to  pale 
green,  gradually  becoming  darker,  until  it  has 
obtained  a  blue  cast,  and  from  that  it  changes  to 
a  purplish  red,  more  or  less  deep,  according  to 
the  quantity  used.  The  succession  of  the  tints 
is  accelerated  by  exposure  to  the  rays  of  the  sun. 
The  stain  given  by  this  animal  fluid,  seems  to  be 
indelible,  bidding  defiance  to  chemical  process, 
and  it  might  therefore  be  most  advantageously 
used  as  a  kind  of  marking  ink. 

The  Buccinum  Lapillus    is  one  of  the  most 

*  Retractile,  capable  of  being  drawn  back,  from  the  Latin  re 
back,  and  tract  us  drawn. 

8* 


90  LESSON   XI. 

common  shells  upon  our  coasts,  adhering  to 
rocks  quite  up  to  high-water  mark. 


BUCCINUM  Subulatum* 
TIGER    SPIRE. 

Specific  character.  Shell  turreted,  subulate, 
smooth ;  colour  white,  tinged  with  yellow,  red, 
or  brown,  and  marked  on  the  body  whorl  with 
three  rows  of  squarish,  dark,  ferruginous!  spots ; 
the  shell  is  from  three  to  six  inches  long,  and 
the  breadth  scarcely  exceeds  one  eighth  of  the 
length. 


GENUS.— STROMBUS.J 

WINGED  OR  CLAW  SHELL. 

Generic  character.  Shell  univalve,  spirally 
convoluted,  canaliculated  ;  form  suboval ;  aper- 
ture more  or  less  dilated,  ending  in  a  beak  turn- 
ing to  the  left,  that  is,  towards  the  outer  lip ;  the 
outer  lip  usually  expanding  into  a  kind  of  wing, 
with  a  sinus  near  the  base. 


*  Piate  III.  figure  4. 

f  Ferruginous,  of  the  colour  of  iron  rust,  from  the  Latin  ferru§ 
o,  rust. 

|  Plate  III.  figure  o. 


STROMBUS — CLAW    SHELL.  91 


OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

A  remarkable  peculiarity  in  the  shells  of  this 
genus  is  their  propensity  to  expand  their  outer 
lip  into  a  wing-like  projection  ;  from  this  circum- 
stance they  are  sometimes  called  the  Alatae,*  or 
winged  shells.  In  some  species  this  expansion 
is  lobed,  in  others  it  is  divided  into  curious  digi- 
tationsf  or  claws,  giving  the  shells  a  resemblance 
to  spiders  or  scorpions,  whence  they  have  re- 
ceived their  specific  names.  Some  are  remark- 
able for  a  lengthened  spire,  and  very  much  re- 
semble in  form  the  Needle  Buccinum.  The 
distinguishing  marks  of  this  genus  are  the  sinus 
in  the  outer  lip  near  the  base,  and  the  position  of 
the  beak. 

The  Strombi,  like  the  Cyprsese,  vary  so  con- 
siderably in  their  different  stages  of  growth,  that 
the  juvenile  specimens  scarcely  bear  the  appear- 
ance of  Strombi :  at  an  early  period  the  outer 
lip  is  not  expanded,  and  there  are  no  traces  of 
claws  ;  subsequently  the  wing  spreads  out>  and 
the  claws  appear  as  short  open  spouts;  and 
when  the  shell  arrives  at  its  full  size,  these  be- 
come solid  hornlike  projections,  often  very  long 
and  curiously  curved. 

There  are  not  more  than  two  or  three  species 
of  the  Strombus  found  on  our  coasts. 


*  Alatae  winged,  from  the  Latin  ala,  a  wing, 
t  Dizitations,  projections  in  the  form  of  fingers,  from  th«  Latin 
Uigit  us,  a  finger. 


92  LESSON  XI 

The  inhabitant  is  little  known,  but  it  is  sup- 
posed from  its  second  sinus  or  notch,  and  its 
curious  digitations,  that  there  must  be  some  pe- 
culiar circumstances  in  its  construction  and 
habits. 

STROMBUS  Pes  Pelicani* 

PELICAN'S  FOOT. 

Specific  character.  Shell  turreted,")*  finely 
striated  transversely;  spire  tapering  to  a  fine 
point  with  ten  tuberculated  convolutions ;  the 
body  whorl  has  two  rows  of  smaller  turbercles 
beneath  the  larger  ones;  outer  lip  much  ex- 
panded, four-clawed,  the  upper  claw  extending 
up  the  spire,  the  lower  one  forming  the  beak  ; 
the  two  middle  digitations  are  ribbed  along  the 
back  in  a  continued  line  from  the  rows  of  tuber- 
cles, and  underneath  is  a  corresponding  groove. 
The  shell  is  of  a  pale  brownish  flesh  colour. 
Length  nearly  two  inches. 

The  Strombus  Pes  Pelicani  is  subject  to  great 
variations  in  the  different  stages  of  its  growth.  In 
young  shellsj  the  outer  lip  has  not  assumed  its 
peculiar  form ;  it  first  gradually  expands,  then 
the  claws  appear,  and  finally  it  becomes  digi- 
tated. Shells  are  found  in  all  the  intervening 
gradations  between  the  young  and  the  adult  spe- 
cimen. 

*  Plate  III.  figure  5. 

f  The  whorls  gradually  decreasing,  the  length  of  the  shell  ex- 
ceeding the  width. 
}  Plate  III.  figure  6. 


MUREX ROCK    SHELL.  93 

The  animal  has  a  long  proboscis  and  two 
thread-shaped  tentacula  of  a  pink  colour. 

This  species  is  rather  common  on  many  of  the 
coasts  of  Great  Britain,  but  is  chiefly  met  with 
on  sandy  shores. 

STROMBUS  Chiragra* 
SAVAGE  CLAW. 

Specific  character.  Shell  ovate,  turreted ; 
spire  short,  tuberculated ;  outer  lip  having  six 
strong  curved  claws,  the  sinus  not  immediately 
at  the  base  ;  mouth  striated ;  colour  white  mot- 
tled with  brown ;  lips  orange  colour  with  black 
and  white  stripes  ;  outside  generally  coated  with 
a  thin  horny  epidermis  ;  size  about  five  inches 
long  and  three  broad,  not  including  the  claws, 
which  are  from  two  to  three  inches  long,  the  up- 
per and  lower  ones  curved  in  opposite  directions. 

This  shell  exhibits  a  very  different  appearance 
at  its  different  periods  of  growth. 


GENUS.— MUREX.f 

ROCK  SHELL. 

Generic  character.      Shell  univalve,    spirally 
convoluted,    canaliculated,  rough    with  spires, 

*  Signifying,  savage  claw,  from  the  Greek  words  *«P,  (cheir) 
hand,  and  aypa,  (agra)  fierce  or  savage. 

f  Probably  named  from  the  Latin,  murex,  the  primary  significa- 
tion of  which  seems  to  have  been  the  sharp  point  of  a  rock.  Plate 
IV.  figure  1,  2,  3. 


94  LESSON   XI. 

tubercles,  or  varices  ;  aperture  oval  ending  in  a 
straight  or  slightly  ascending  canal.     Some  of 
the  species  are  remarkable  for  the  great  lengt 
of  the  beak. 


OBSERVATIONS  ON  THE   SHELL  AND  ITS 
INHABITANT. 

The  very  great  variety  which  occurs  in  the 
shells  of  this  genus  has  caused  them  to  be  ar- 
ranged under  several  divisions  ;  but  the  mark  by 
which  a  Murex,  according  to  the  Linnaean  de- 
finition, may  be  easily  recognised,  is  the  oval 
shape  of  the  mouth  ;  for  this  is  preserved  even 
when  the  aperture  is  terminated  by  a  beak,  as 
instead  of  gradually  contracting,  it  abruptly  opens 
into  a  canal.  Besides  this  regularity  in  the  out- 
line of  the  aperture,  the  beak  neither  inclines  to 
the  right  nor  to  the  left. 

The  Murices  are  in  general  of  an  irregular 
form,  arising  from  their  surfaces  being  covered 
either  with  spines,  tubercles,  varices,  or  folia- 
tions ;  and  from  the  rock- like  and  rugged  appear- 
ance thus  occasioned  they  derive  their  designa- 
tion. Many  of  the  shells  of  this  genus  are  re- 
markable for  the  singular  extension  of  their 
beak.  Those  of  one  division  are  elegantly 
adorned  with  foliated  expansions  ;  they  were 
anciently  called  Purpurae,  because  the  animals 
inhabiting  them  yielded  the  famous  purple  dye. 

Many  of  the  Murices  are  distinguished  by 
their  thick  protuberent  rounded  varices.  These 
shells  have  been  divided  into  different  genera 


MUREX — ROCK  SHELL.  95 

according  to  the  arrangement  of  these  ornaments. 
One  division  of  shells  called  Ramella,*  Frog, 
from  their  resemblance  to  that  animal,  are  dis- 
tinguished by  having  two  varices  in  each  whorl, 
and  these  are  continued  in  a  longitudinal  series 
on  each  side  up  to  the  apex,  giving  the  shell  a 
flattened  appearance  on  the  front  and  back. 

The  shells  of  another  division")"  are  distin- 
guished by  three  rows  of  varices,  so  arranged 
that  they  form  three  longitudinal  raised  lines 
taking  rather  an  oblique  inclination  towards  the 
apex.  It  is  evident  that  the  habits  of  the  mol- 
lusca  of  these  two  sets  of  shells  must  be  diffe- 
rent, for  the  situation  of  the  varices  of  the  latter 
proves  that  a  smaller  portion  is  added  to  the 
abode  at  each  epoch  of  its  growth  than  in  the 
Ramella. 

A  third  division  J  of  this  genus  includes  shells 
ornamented  by  varices,  not  disposed  in  a  con- 
tinued series  as  in  the  other  two  classes.  This 
difference  in  the  disposition  of  these  protube- 
rances is  occasioned  by  the  piece  which  the  ani- 
mal adds  to  its  shell  being  more  than  half  a  volu- 
tion. The  varices  are  consequently  few,  and 
appear  scattered  over  the  shell. 

MUREX  Ramosus.§ 
BRANCHED    MUREX. 

Specific  character.  Shell  oval,  somewhat 
nodulous,  with  three  foliated  varices ;  beak  short 

*  Plate  IV.  fisrnre  2.  f  plate  IV-  fi£nre  1. 

t  Plate  IV.  figure  3.  $  Plate  IV.  figure  1. 


96  LESSON  XI. 

and  truncated ;  the  colour  of  this  shell  varies 
greatly,  it  is  sometimes  of  an  uniform  whiteness, 
sometimes  pale  yellow  brown,  pale  red,  nearly 
black,  and  sometimes  the  whorls  are  of  one  of 
these  colours,  and  the  foliations  of  another.  Its 
dimensions  also  are  very  different ;  it  varies  from 
two  to  five  inches,  and  is  about  half  as  broad. 

This  Murex  belongs  to  the  shells  called  Pur- 
purse.  An  expression  of  Yirgil  implies  that  the 
Tyrian  dye  was  extracted  from  this  shell  in  his 
time :  He  says,  "  glowing  with  Tyrian  Murex." 
The  Tyrians  were  the  most  successful  among 
the  ancients  in  preparing  and  using  this  cele- 
brated colour.  The  Mediterranean  supplied 
them  with  the  mollusca  in  abundance,  and  in 
order  to  produce  the  tint  that  was  in  highest  esti- 
mation, a  bath  of  the  liquid  extracted  from  the 
animal  of  the  Murex  was  prepared.  In  this  they 
steeped  the  wool  for  a  certain  time ;  when  taken 
out  they  immersed  it  in  another  boiler,  which 
contained  an  extract  from  the  Buccinum  alone. 
Wool  which  had  been  subjected  to  this  double 
process  was  so  highly  valued,  that  in  the  reign 
of  Augustus  each  pound  of  it  sold  for  about  ^£36 ; 
nor  shall  we  wonder  at  its  being  valued  at  such 
an  enormous  price,  when  it  is  recollected  that 
only  a  single  drop  of  the  colouring  fluid  is  af- 
forded by  each  animal. 

This  beautiful  and  precious  colour  was  held 
in  the  highest  estimation  by  the  ancients,  and  in 
some  countries  it  was  consecrated  to  sacred 
uses.  Moses,  under  divine  instruction,  used 
purple  stuffs  for  the  furniture  of  the  tabernacle, 


MUREX — ROCK  SHELL.  97 

and  for  the  dress  of  the  high  priest.  The  Baby- 
lonians arrayed  their  idols  in  robes  of  splendid 
purple  ;  and  such  indeed  was  the  practice  of  the 
Pagans  in  general,  many  of  whom  superstitiously 
believed  that  this  dye  had  a  peculiar  virtue,  and 
was  capable  of  appeasing  the  wrath  of  their  pre- 
tended gods. 

Purple  robes  were  also  characteristic  of  regal 
dignity,  and  by  an  imperial  decree  in  Rome, 
they  were  entirely  restricted  to  the  use  of  the 
emperor,  the  penalty  of  death  being  inflicted  on 
any  who  dared  to  appear  in  habiliments  of  this 
hue.  The  language  of  the  day  shows  how  ex- 
clusively this  colour  is  appropriated  to  the  em- 
perors, for  "  to  assume  the  purple,"  signified  the 
being  elevated  to  the  Imperial  Throne. 

Several  different  accounts  are  given  of  the 
discovery  of  this  dye  ;  but  they  all  seem  to  have 
originated  in  the  simple  fact,  that  a  dog  having 
broken  one  of  the  shells,  stained  his  mouth  with 
the  colour  from  the  animal,  which  excited  the 
attention  of  his  owner,  and  led  to  an  examination 
of  the  cause. 

The  vast  heaps  of  fragments  of  shells  found 
about  Tarentum,  are  supposed  to  be  those  from 
which  the  celebrated  dye  was  extracted,  and 
seem  to  indicate  that  place  as  one  where  it  was 
prepared ;  it  has  not  been  ascertained  to  what 
species  these  shells  belong. 


98  LESSON 


MUREX  Tribulus. 

THORNY  WOODCOCK. 

Specific  character.  Shell  subovate,  with  three 
spinous  varices  :  spines  continued  to  the  ex- 
tremity of  the  beak,  which  is  long  ;  between  the 
varices  the  shell  is  transversely  ribbed  and 
slightly  nodulous  ;  the  colour  is  dirty  white,  or 
pale  brownish  white  ;  the  shell  is  about  three  or 
four  inches  in  length,  of  which  the  subulate  beak 
occupies  the  larger  part;  the  breadth  of  the 
body  whorl  is  about  an  inch  and  a  quarter,  or  an 
inch  and  a  half. 

This  shell  is  found  in  the  Asiatic  and  American 
seas  and  in  the  Red  Sea.  It  was  first  discovered 
by  a  singular  accident.  A  diver  feeling  a  sharp 
pain  from  something  having  pierced  his  foot*  and 
apprehending  that  it  might  be  the  bite  of  some 
venomous  animal,  immediately  gave  the  signal 
to  be  drawn  up,  and  seeking  for  the  cause,  dis- 
covered one  of  these  shells,  the  thorns  of  which 
had  entered  his  flesh. 


MUREX  Tritonui. 

TRITON'S  TRUMPET. 

Specific  character.  Shell  ventricose,  with 
alternate  varices,  and  slightly  elevated  transverse 
ribs,  the  interstices  striated ;  the  whorls  ere- 


TROCHUS — TOP  SHELL.  99 

nated*  at  the  suture ;  columellar  lip  grooved, 
beak  short  and  ascending  ;  colour  whitish,  orna- 
mented on  the  ribs  with  parallel  curved  reddish 
brown  spots,  which  are  shaded  off  to  wards  each 
other  ;  columellar  lip  striped  with  dark  brown  ; 
the  length  is  a  foot,  sometimes  sixteen  inches, 
and  the  breadth  about  half  as  much. 

It  inhabits  the  Asiatic  seas,  and  those  of  the 
Torrid  zone  in  general.  It  is  used  by  the  na- 
tives of  New  Zealand  as  a  musical  instrument, 
and  by  the  Africans  as  a  military  trumpet.  It  is 
supposed  to  be  the  shell  intended  by  Ovid,  when 
he  describes  the  waters  of  the  deluge  retiring  on 
the  sound  of  the  trumpet  of  Triton. 


GENUS— TROCHUS.t 

TOP  SHELL. 

Generic  character.  Shell  univalve,  spirally 
convoluted ;  form  more  or  less  conical ;  aperture 
entire,  quadrangular,  sometimes  approaching  to 
round,  generally  wider  than  it  is  long ;  margins 
separated ;  columella  oblique. 

*  Crenated,  being  notched,  from  the  Latin  cren  o,  the  notch 
an  arrow, 
off  Plate  IV.  figures  4, 5,  6. 


100  UNIVALVES. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

Many  of  the  Trochi  so  nearly  resemble  the 
shells  in  the  following  genus,  that  it  is  often  dif- 
ficult to  discriminate  between  them.  The  cha- 
racter by  which  they  are  most  readily  known,  is 
the  angular  contour  of  the  mouth.  Their  true 
form  is  that  of  a  pointed  cone,  capable  of  stand- 
ing nearly  perpendicular,  or  but  little  inclined  on 
its  base.  Some  of  these  erect  shells*  have  their 
columella  umbilicated,  somef  are  imperforate. 
A  few  of  the  Trochi  are  elongated, J  resembling 
in  form  the  Needle  Buccinum ;  these  have  an 
exserted  columella,  and  when  placed  on  their 
base,  fall  on  one  side. 

Many  of  the  shells  of  this  genus  have  their 
outside  rough  with  tubercles,  and  many  are  co- 
vered with  a  thick  epidermis,  on  the  removal  of 
which  a  bright  surface  appears,  shining  with  iri- 
descent colours.  The  animals  which  inhabit 
these  shells  have  no  proboscis,  but  a  mouth 
armed  with  two  jaws,  and  thence  it  is  concluded 
that  they  feed  upon  vegetables ;  the  shell  also 
has  neither  notch  nor  canal,  and  the  mollusca  no 
siphon. 

*  Plate  IV.  figure  5.  f  Plate  IV.  figure  4. 

I  Plate  IV.  figure  6. 


TROCHUS — TOP   SHELL.  101 

TROCHUS  Perspective* 
STAIRCASE  TROCHUS. 

Specific  character.  Shell  conical,  obtusely 
marginated  at  the  base  ;  umbilicated;  the  um-^ 
bilicus  large,  funnel-shaped,  round  which  the 
whorls  wind  spirally,  having  a  crenated  margin ; 
aperture  nearly  quadrangular ;  shell  flat  under- 
neath, longitudinally  and  transversely  striated  ; 
colour  greyish,  beautifully  variegated  with  och- 
rous  brown  spots. 

Inhabits  the  shores  of  Asia  :  frequent  about 
Alexandria. 

TROCHUS  Conrfiyliophorus. 
CARRIER  TROCHUS. 

Specific  character.  Shell  conical,  coarse, 
obtusely  plaited.  Whorls  imbricated,!  base  con- 
cave, colour  brownish  white  ;  size  an  inch  and  a 
half  long,  and  an  inch  and  three  quarters  broad. 

A  singular  fact  in  the  natural  history  of  this 
shell  is,  that  it  accumulates,  during  its  formation, 
different  foreign  substances,  and  is  often  found 
covered  with  stones,  coral,  small  shells,  and 
fragments  of  shells ;  on  account  of  this  curious 
property,  it  has  acquired  the  name  of  the  Carrier, 
It  has  not  been  ascertained  how  this  animal, 

*  Plate  IV.  figure  5. 

f  Imbricated,  tiled,  from  the  Latin  imbrex,  a  tile 

9* 


102  UNIVALVES. 

during  the  formation  of  its  shell,  collects  these 
various  substances ;  probably  some  very  tena- 
cious matter  is  combined  with  its  calcareous 
secretions,  which  cause  whatever  comes  in  con- 
tact with  it  before  it  is  hardened,  to  adhere  to  its 
surface. 


GENUS— TURBO.* 

TURBAN-SHELL. 

Generic  character.  Shell  univalve,  spirally 
convoluted,  solid  ;  shape  more  or  less  conical ; 
aperture  entire,  contracted,  orbicular. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  shells  of  this  and  the  preceding  genus 
are  often  so  similar,  that  it  is  difficult  to  define 
the  boundaries  by  which  they  are  separated  ;  the 
mouths  of  the  Trochi  gradually  losing  the  an- 
gular, and  assuming  the  orbicular  form  ;  whilst 
many  species  of  the  Turbines  exhibit  a  very  im- 
perfectly circular  aperture.  The  names  of  both 
these  genera  imply  any  thing  that  whirls  round  ; 
they  both  exhibit  a  conical  form,  and  are  also 
nearly  allied  in  habits,  as  well  as  in  appearance. 
The  marine  species  are  found  on  rocks  and 

*  Plate  IV.  figures  7,  8. 


TURBO — TURBAN  SHELL.       103 

craggy  shores,  or  on  the  sand,  when  detached  by 
a  storm  from  their  customary  abode. 

There  is  no  indication  in  the  shells  of  either 
genus  of  an  increase  in  growth  after  the  first 
formation.  There  are  several  species  of  Needle 
or  Screw-shells  among  the  Turbines  ;  they  are 
distinguished  by  their  circular  mouth,  from  those 
of  a  similar  form  in  other  genera ;  their  shape  is 
that  of  a  well-proportioned  spire,  formed  by 
thirty  or  forty  whorls,  gradually  tapering  from  the 
base  to  the  apex,  and  terminating  in  a  fine  point. 
There  are  upwards  of  seventy  species  of  this 
genus  among  British  shells,  and  several  of  them 
are  terrestrial.  One  called  Turbo*  Fasciatus,  is 
found  so  abundantly  in  a  part  of  Cornwall,  that 
it  is  impossible  to  take  a  step  without  crushing 
numbers.  It  is  the  prevailing  opinion,  that  they 
contribute  much  to  fatten  sheep  ;  they  spread 
themselves  over  the  plain  and  hill  near  Whitsand 
Bay,  Cornwall,  and  the  sheep  which  browse  on 
the  short  herbage,  must  devour  a  prodigious 
quantity  of  these  mollusca,  which  early  in  the 
morning  ascend  the  short  blades  in  quest  of 
their  own  food.  Some  very  small  Turbines,  are 
found  abundantly  on  old  walls  amidst  moss. 

*  Turbo,  the  Latin  for  a  whirlwind ;  trochus,  a  top. 


104  UNIVALVES. 

TURBO  Littoreus.* 
PERIWINKLE 

Specific  character.  Shell  strong,  sub-oval ; 
body-whorl  large,  the  others,  four  or  five  in 
number,  small  and  nearly  flat,  separated  only  by 
a  fine  line  ;  aperture  suborbicular,  outer  lip  thin, 
inner  flat  and  thick.  When  full  grown  it  is 
nearly  smooth  and  of  an  uniform  brownish  co- 
lour, but  the  younger  shells  are  more  distinctly 
striated  and  variously  marked  with  purple,  white, 
yellow,  or  red  bands ;  size,  about  three  quarters 
of  an  inch  long,  and  nearly  equally  broad. 

The  Periwinkle  is  extremely  abundant  on  the 
shores  of  Great  Britain ;  it  is  often  sold  in  our 
seaport  towns,  and  when  boiled,  eaten  by  the 
lower  classes.  It  is  found  on  rocks  usually 
above  low  water  mark.  The  Swedish  peasants 
affirm,  that  when  the  animals  of  this  species 
ascend  the  rocks,  it  is  a  sure  sign  of  an  ap- 
proaching storm,  as,  prompted  by  instinct, 
they  place  themselves  out  of  the  reach  of  the 
dashing  of  the  waves ;  on  the  contrary,  that 
when  they  make  their  descent  into  the  sand,  it 
is  an  indication  of  a  calm.  The  mollusca  of 
the  Periwinkle  are  striped  with  black ;  they 
have  two  setaceous  tentacula  annulated,'}*  or 

*  Littoreus  is  derived  from  the  Latin  word  littus,  a  shore.  The 
littoral  species  are  those  which  burrow  in  the  sand,  or  adhere  to 
the  rocks  when  left  dry  by  the  receding  tide. 

tFrom  annulus,  the  Latin-word  for  a  ring 


TURBO — TURBAN  SHELL.      105 

streaked  transversely  with  black ;  the  eyes  are 
at  the  base  of  the  tentacula,  and  are  very  pro- 
minent. 

TURBO  Scalaris* 
WENTLE-TRAP.f 

Specific  character.  Shell  turreted,  with  eight 
rounded  detached  whorls,  connected  only  by 
elevated  acute  oblique  ribs  ;  the  aperture  round, 
thickened,  and  reflected  ;  the  colour  snow-white, 
sometimes  pale  flesh  colour ;  the  size  varies  from 
an  inch  and  half  to  two  inches  in  length.  The 
aperture  is  closed  by  a  horny  spiral  operculum. 

This  elegant  shell  is  valued  when  perfect  at 
a  high  price,  on  account  of  its  rarity.  The  nu- 
merous ribs  mark  the  different  periods  of  its  in- 
crease, and  are  in  fact  the  reflected  margins  of 
its  former  apertures,  produced  at  its  various 
stages  of  growth.  It  is  found  in  the  warm  seas 
of  the  east.  There  is  a  shell  which  inhabits  the 
European  and  American  seas,  and  is  found  upon 
our  coasts,  though  not  abundantly,  called  Turbo 
Clathrus,  or  False  Wentle-trap.  J  It  differs  from 
the  true  Wentle-trap  principally,  in  having  its 
whorls  contiguous.  The  inhabitant  is  one  of  the 
animals  that  yield  a  purple  dye  :  if  kept  some 
days  out  of  water  it  becomes  sickly,  and  dis- 
charges a  most  beautiful  purple  liquid.  This 

*  Plate  IV.  figure  7. 

t  A  corruption  of  the  German  windel-treppe,  a  winding  staircase, 

J  Plate  IV.  figure  3. 


106  UNIVALVES. 

V 

dye  differs  in  many  respects  from  that  obtained 
from  the  Buccinum  Lapillus.  It  can  be  pro- 
duced spontaneously  from  the  mollusca ;  the 
colour  when  first  discharged  from  the  animal  is 
purple,  and  not  of  the  same  unalterable  nature 
as  that  obtained  from  the  other  shell. 


GENUS^-HELIX.* 

SNAIL. 

f  Generic  character.  Shell  univalve,  spirally 
convoluted,  sub-diaphanous,")*  thin  and  fragile  ; 
aperture  entire,  contracted,  sub-orbicular ;  body 
whorl  generally  projects  into  the  mouth,  sepa- 
rating the  lips. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  shape  of  the  Helix  varies  considerably : 
some  of  the  species  exhibit  quite  a  turreted 
form  ;J  in  others  the  whorls  are  arranged  on  a 
horizontal  plane, §  so  that  the  spire  is  quite  flat- 
tened, and  the  course  of  the  volutions  may  be 

*  Plate  V.  figures  1, 2,  3. 

f  Diaphanous  is  from  the  Greek  words  &a,  (dia)  through,  and 
<f>aivta,  I  appear. 

I  Plate  V.  figure  3 

II  Plate  V.  figure  2. 


HELIX — SNAIL.  107 

seen  either  from  the  'upper  or  under  part  of  the 
shell.  Many  display  a  form  between  these  two 
extremes  ;  -  others  again  are  turbinate,  and  of  a 
globose  appearance.* 

There  is  not,  perhaps,  any  part  of  animated 
nature  more  abundant  or  universally  diffused 
than  snails  ;  the  butterfly  alone  can  compete  with 
them  in  this  respect.  They  are  found  in  the 
most  barren  and  desert  wastes.  There  are  parts 
of  the  great  Sahara  destitute  of  all  manner  of 
herbage,  except  here  and  there  a  tuft  of  coarse 
grass,  or  a  solitary  stunted  laurel,  which,  accor- 
ding to  the  Psalmist's  description,  "  withe  re th 
before  it  be  plucked  up."  Yet  these  parched 
specimens  of  vegetation  are  sometimes  quite 
studded  with  snails.  It  has  often  been  conjec- 
tured, that  snails  were  in  part  the  food  of  the 
Israelites,  when  they  took  their  rapid  flight  from 
Egypt ;  for  the  country,  through  which  they 
passed  in  their  way  to  the  Red  Sea,  is  described 
by  one  who  traversed  it,  as  having  a  herbage 
underneath  the  trees  and  shrubs,  which  is  com- 
pletely covered  with  snails  of  a  prodigious  ske, 
and  of  the  best  sort ;  and  in  that  country  these 
animals  are  esteemed  a  delicacy. 

Snails  furnish  a  valuable  article  of  food  on 
the  shores  of  the  Mediterranean,  where  they  are 
boiled  in  their  shells,  and  served  up  with  rice. 
They  possess  nearly  the  same  nutritious  qualities 
as  oysters,  and  the  use  of  them  has  often  proved 
efficacious  in  consumptive  disorders. 

*  Plate  V.  figure  1. 


108  UNIVALVES. 

The  Helices  which  live  on  land  become  torpid 
on  the  approach  of  winter,  and  generally  cover 
the  mouth  of  their  shell  with  an  operculum. 
Like  that  of  other  terrestrial  mollusca,  this  co- 
vering is  not  attached  to  the  animal,  but  to  the 
shell,  and  is  deciduous,  acting  only  as  a  preser- 
vative against  the  cold  of  winter. 

The  history  of  this  genus  is  very  interesting 
and  instructive,  affording  a  striking  instance  of 
the  superintending  providence  of  the  Almighty, 
and  his  care  for  the  peculiar  wants  of  His  crea- 
tures; though  all  things  are  at  his  command, 
He  is  not  prodigal  of  means  ;  He  gives  what  is 
required,  and  holds  back  what  is  needless.  Upon 
the  animals  who  inhabit  the  rocky  shores,  or 
bottom  of  the  ocean,  He  has  bestowed  a  thick 
substantial  covering ;  but  to  snails,  the  greater 
number  of  which  live  on  the  land,  or  in  stagnant 
pools,  or  peaceful  streams,  He  has  given  a  thin 
and  remarkably  light  shell,  which,  while  it  affords 
ample  protection  to  its  inmate,  offers  no  impedi- 
ment to  its  locomotive  propensities.  Can  we 
see  this  beautiful  adaptation  to  circumstances — 
this  provision  for  the  wants,  and  consideration 
for  the  comforts  of  His  creatures,  and  not  give 
the  praise  and  adoration  to  Him,  who  riding 
upon  the  wings  of  the  winds,  regards  not  only 
the  sons  of  men,  but  the  meanest  reptile  that 
crawls  upon  the  earth  ! 


HELIX — SNAIL.  109 

HELIX  Pomatia* 
EATABLE  SNAIL. 

Specific  character.  Shell  nearly  globular, 
turbinate,  with  five  rounded  whorls  strongly 
wrinkled  longitudinally;  aperture  semi-lunar, 
margin  rather  thickened,  and  turned  a  little  out- 
wards ;  the  columellar  lip  much  reflected  over 
the  umbilicus ;  colour  dingy  yellowish  brown, 
commonly  with  three  faint  bands  on  the  body 
whorl,  one  of  which  continues  round  the  next 
whorl ;  size  about  two  or  three  inches  in  length, 
and  nearly  equal  in  breadth. 

This  is  the  largest  species  of  land  shell  found 
in  England.  It  is  not  a  native  of  this  country, 
but  was  originally  introduced  about  the  middle 
of  the  sixteenth  century,  either  as  an  article  of 
food,  or  for  medicinal  purposes.  It  is  supposed 
to  have  been  first  imported  from  Italy  into  Surrey, 
by  a  Mr.  Howard  of  Albury ;  the  animals  in- 
creased there  prodigiously,  and  are  now  become 
the  most  common  species  about  Box  Hill,  Ash- 
stead,  and  that  neighbourhood.  They  were  in- 
troduced into  Buckinghamshire  as  a  medicine 
for  a  lady  who  was  in  a  consumption.  They  are 
commonly  used  as  food  by  the  Roman  Catholics 
in  many  parts  of  Europe  during  Lent,  and  are 
preserved  and  fattened  for  that  purpose  in  large 
reservoirs,  the  floors  of  which  are  covered  with 
herbs  and  flowers.  These  mollusca  were  among 

*  Plate  V.  figure  1. 
10 


110  UNIVALVES. 

the  dainties  of  the  luxurious  Romans,  who  had 
their  Cochlearia,  or  nurseries  for  snails,  where 
the  animals  were  fed  on  bran  and  wine,  till  they 
increased  to  such  a  size,  that  if  we  may  credit 
Varro,  a  shell  has  been  known  sufficiently  large 
to  contain  ten  quarts  of  liquid.  It  is  mentioned 
as  a  remarkable  fact  relating  to  this  shell,  that 
when  the  animal  is  in  a  diseased  state,  the  spire 
becomes  much  elongated. 


HELIX  Hortensis. 
GARDEN  SNAIL. 

Specific  character.  Shell  subglobular,  smooth, 
diaphanous  with  fine  transversely  banded- whorls ; 
aperture  roundish,  semiorbicular,  the  outer  lip 
slightly  reflected ;  the  colour  of  the  shell  and  the 
bands  are  exceedingly  various ;  greatest  dia- 
meter less  than  an  inch. 

This  is  the  most  common  species  of  snail.  At 
the  approach  of  winter  forming  an  operculum  of 
a  coriaceous  substance,  composed  of  several 
coatings,  and  finding  a  retreat  at  the  roots  of 
trees,  and  under  old  walls,  it  braves,  the  rigours 
of  the  season.  Its  circulation  is  most  remarkably 
sluggish,  and  its  movements  are  correspondingly 
slow ;  but  the  thick  juices  which  prevent  its  ac- 
tivity, enable  the  snail  to  bear  the  severity  of  win- 
ter, so  that  no  cold,  however  intense,  has  been 
known  to  freeze  it.  Again,  these  juices,  though 
they  retard  the  progress  of  the  animal,  furnish  it 
by  means  of  their  viscidity,  with  the  power  of 


HELIX SNAIL.  Ill 

travelling  with  its  house  on  its  back  up  perpen- 
dicular ascents,  or  across  horizontal  surfaces. 
Snails  do  not  usually  crawl  out  in  search  of 
nourishment,  except  in  rainy  seasons,  or  in 
damp  and  shady  places  ;  in  time  of  drought,  they 
take  their  station  under  stones  and  leaves,  or  in 
the  cavities  of  the  trunks  of  trees. 


HELIX  JantMna. 
VIOLET  SNAIL. 

Specific  character.  Shell  univalve,  with  four 
whorls  obliquely  situated,  subglobular,  thin,  fra- 
gile, diaphanous ;  aperture  subtriangular,  the 
angle  formed  by  the  upper  and  lower  part  of  the 
outer  lip  rounded ;  columella  straight ;  colour 
violet,  palest  towards  the  summit ;  size  an  inch 
long,  the  breadth  rather  exceeds  the  length. 

This  shell,  beautiful  in  its  form  and  colour,  is 
still  more  interesting  in  its  history,  as  displaying 
another  instance  of  the  overruling  care  of  the 
Creator,  and  of  his  compensatory  providence. 
Unlike  most  fragile  shells,  its  dwelling  is  the 
stormy  ocean  ;  but  as  the  feeble  reed  bends  to 
the  mighty  wind,  and  rises  unhurt  when  its  power 
is  suspended,  so  this  delicate  shell  offering  no 
resistance  to  the  sea,  rides  upon  its  waves  in 
perfect  safety.  It  is  always  found  floating  upon 
the  water,  and  probably  never  visits  the  bottom, 
or  willingly  approaches  any  shore.  It  is  thus 
supported  on  the  surface  by  means  of  a  small 


UNIVALVES. 

cluster  of  bubbles  composed  of  transparent  vesi- 
cles, which  it  can  inflate  with  air  at  pleasure,  and 
thus  buoy  up  its  delicate  bark.  Every  shell 
contains  about  a  teaspoonful  of  liquor  of  a  most 
beautiful  red  purple,  which  is  easily  discharged, 
as  soon  as  the  animal  is  touched.  It  is  said  also 
to  shine  by  night  with  a  phosphorescent  light.  It 
inhabits  the  coasts  of  Europe,  Asia,  and  Africa, 
and  is  common  in  the  Mediterranean.  A  few 
specimens  have  been  picked  up  on  the  Welsh 
coasts,  but  these  were  probably  driven  there  by 
storms. 

HELIX  Obscura. 
SMALL  BROWN  SNAIL. 

Specific  character.  Shell  sub-oval,  rather  ob- 
tuse, opaque,  with  about  six  longitudinally 
wrinkled  whorls ;  aperture  roundish,  lunar ;  it  is 
of  a  brownish  horn  colour,  and  the  outer  lip 
white,  with  a  reflected  margin ;  length  half  an 
inch,  breadth  one  fourth,  or  one  sixth.  These 
shells  are  usually  covered  with  an  epidermis, 
which  varies  according  to  the  situations  they 
occupy  ;  and  the  colour  being  regulated  by  that 
of  the  substance  to  which  the  Helices  attach 
themselves,  they  escape  observation. 


NERITA NERITE.  113 

GENUS— NERITA.* 

NERITE  OR    HOOF-SHELL. 

Generic  character.  Shell  univalve,  spirally 
convoluted,  retuse,  gibbous,  flattish  underneath ; 
aperture  semilunar ;  columellar  lip,  truncated, 
flattish,  straight,  and  oblique  to  the  axis  of  the 
shell. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

There  is  no  genus  more  easily  distinguished 
than  that  of  the  Nerites.  The  semilunar  aper- 
ture and  straight  flat  columellar  lip  are  its 
decided  characteristics.  There  are  a  few  species 
which  might  pass  for  Turbines,  the  columellar 
lip  not  preserving  its  straightness  ;  but  even  in 
these  doubtful  shells  it  is  flat,  and  therefore  their 
proper  place  in  this  genus  is  obvious.  Some  of 
the  species  have  an  umbilicus  ;  and  in  some  the 
columeilar  lip  is  beset  with  strong  teeth.  The 
Nerites  are  all  either  fluviatile  or  marine,  the 
latter  are  distinguished  by  their  solid  and  sub- 
stantial shells. 

Nothing  can  exceed  the  beauty  and  delicacy 
of  the  miniature  painting  with  which  many  of 
this  genus  are  adorned ;  when  viewed  through  a 
microscope,  the  most  highly  finished  touches 
are  discernible.  Many  species  have  elevated 

*  Plate  V.  figures  4,  5. 
10* 


114  UNIVALVES. 

rounded  ribs,  sometimes  minutely  striated.  They 
are  worn  as  ornaments  by  the  Indians. 


NERITA  Peloronta* 
BLEEDING    TOOTH. 

Specific  character.  Shell  solid,  thick,  semi 
globular,  turbinate,  imperforate,  slightly  ribbed 
transversely;  spire  flat;  aperture  entire,  semi- 
lunar  ;  outer  lip  crenulate,  inner  lip  rather  con- 
cave, with  two  or  three  large  teeth  and  an 
irregular  saffron  or  blood-coloured  spot  in  the 
middle  ;  ground  of  the  shell  whitish  or  pale  grey 
with  irregular  black  and  red  or  purplish  longitu- 
dinal zig-zag  markings ;  aperture  white,  and 
throat  pale  saffron-colour. 

The  shells  of  this  species  inhabit  the  ocean, 
and  are  found  in  the  West  Indies,  Red  Sea, 
and  Molucca  Islands.  The  animal  is  furnished 
with  an  operculum  which  opens  and  shuts  at  its 
pleasure,  like  a  door  upon  its  hinges,  having  a 
little  prominence  within  the  shell,  at  the  lower 
end  of  the  lip,  between  which  and  the  inner  lip 
a  small  projection  of  the  operculum  slides  as  it 
opens. 

NERITA  Corona. 

Specific  character.  Shell  globose,  striated, 
spire  short,  eroded,|  body  whorl  large  with  a 

*  Plate  V.  figure  4. 

f  Eroded,  gnawed  out,  from  Latin  e,  out,  and  rod  ere,  to  gnaw. 


NERITA NERITE.  115 

transverse  row  of  long  spines  ;  generally  coated 
with  a  black  epidermis ;  length  from  half  to  three 
quarters  of  an  inch,  about  two  thirds  as  broad. 

This  shell  has  an  operculum,  which  is  testa- 
ceous, covered  with  a  horny  epidermis  of  a  semi- 
circular form,  exactly  closing  the  aperture,  and 
furnished  internally  with  a  dentiform  appendage, 
which,  when  the  aperture  is  closed,  lies  between 
a  prominence  at  the  lower  part  of  the  aperture, 
and  the  end  of  the  inner  lip. 

The  columella,  together  with  the  inner  part  of 
the  spire,  and  even  a  part  of  the  lip  is  absorbed 
by  the  animal,  in  proportion  as  it  increases  in 
size,  whence  it  appears  to  have  no  columella. 


NERITA  Littoralis. 
STRAND    NERITE. 

Specific  character.  Shell  thick,  smooth,  sum- 
mit rather  obtuse;  whorls  four  or  five,  body 
whorl  large,  the  others  small  and  lateral ;  aper- 
ture lunar,  rather  inclining  to  oval ;  columellar 
lip  not  so  flat  as  usual  in  this  genus ;  colour 
various,  commonly  plain  light  or  orange  yellow, 
red  or  brown,  sometimes  prettily  mottled,  or 
marked  with  one  or  two  paler  transverse  bands ; 
size  about  three  fourths  of  an  inch  long,  breadth 
rather  exceeding  the  length. 

This  species  is  extremely  common  on  all 
our  shores,  varying  considerably  in  colour  and 
shape :  its  roundish  mouth  and  accidental  re- 


116  UNIVALVES. 

semblance   of  colour   have   occasioned   some 
specimens  to  be  described  as  Turbines. 


GENUS.— HALIOTIS* 

SEA-EAR  OR  EAR-SHELL. 

Generic  character.  Shell  univalve,  dilated, 
ear-shaped;  spire  flat,  lateral,  retuse,  nearly 
concealed ;  aperture  almost  as  large  as  the  shell ; 
the  disk,*  excepting  in  one  or  two  species,  has  a 
series  of  perforations  parallel  to  the  columellar 
margin. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  ear-like  shape,  the  flattened  spire  and  the 
row  of  perforations  on  the  disk  readily  distinguish 
this  genus  from  every  other.  The  outside  of  the 
shell  is  generally  rough,  worn  or  covered  with 
marine  substances.  The  inside  is  enamelled  with 
mother-of-pearl,  exhibiting  a  beautiful  iridescent 
play  of  colours.  Each  period  of  the  shell's  in- 
crease is  marked  by  a  new  hole,  and  till  the  final 
addition  is  made,  there  is  a  notch  in  the  last  per- 
foration in  which  the  animal  places  its  siphon. 

*  Plate  V.  figure  2. 

f  Disk,  a  rounded  surface,  from  the  Latin  discus,  a  dish  or 
platter. 


HALIOTIS SEA-EAR.  117 

When  a  new  hole  is  opened,  one  toward  the 
spire  is  closed,  and  there  are  seldom  more  than 
seven  or  eight  unstopped  at  the  same  time. 
When  the  Haliotides  traverse  the  rocks,  their 
shell  is  like  a  reversed  basin,  and  the  circum- 
ference is  bordered  by  the  foot  of  the  animal, 
which  is  very  large  ;  the  spire  is  at  the  posterior 
part  as  it  advances.  In  their  repose  they  adhere 
to  the  rocks  with  such  tenacity  that  it  requires 
the  utmost  force  to  disengage  them,  though  they 
can  with  the  greatest  facility  remove  themselves. 
They  are  always  found  near  the  surface  of  the 
water,  and  in  serene  summer  nights  they  feed  on 
the  vegetation  which  springs  up  on  the  shore. 
All  the  shells  of  this  genus  are  marine,  as  the 
name  implies,  being  derived  from  fas  (hals)  sea, 
and  wra  (bta)  ears.  Most  of  the  species  inhabit 
the  seas  of  warm  climates.  They  have  no  oper- 
culum. 

HALIOTIS  Tuberculata* 

COMMON  SEA-EAR. 

Specific  character.  Shell  strong,  thick,  sub- 
ovate,  transversely  wrinkled,  striated  longitudi 
nally,  and  tuberculated  ;  near  the  inner  margin 
is  a  ridge  extending  the  length  of  the  shell,  and 
terminating  in  one  spiral  turn  at  the  end,  a  little 
produced;  this  ridge  is  beset  with  tubercles 
which  increase  in  size  as  they  recede  from  the 

*  Plate  IV.  figure  2. 


118  UNIVALVES. 

apex ;  the  last  six  are  open ;  when  cleared  of 
extraneous  matter  with  which  it  is  constantly 
covered,  the  outside  is  of  a  reddish  brown  colour 
frequently  mottled  ;  the  inside  is  a  beautiful 
mother-of-pearl.  The  outer  lip  forms  a  flat  ridge 
quite  up  to  the  spire,  and  is  pearly  like  the  in- 
side ;  the  length  is  from  three  to  four  inches, 
the  breadth  between  two  and  three. 

These  shells  inhabit  the  deep  ;  and  they  are 
sometimes  thrown  upon  our  southern  coasts  after 
violent  storms.  In  Guernsey  they  are  found  in 
great  plenty  adhering  to  the  rocks  at  the  lowest 
ebb  tide.  The  animal  is  eaten,  and  forms  a  very 
savoury  dish  ;  the  shells  are  used  to  adorn  the 
houses  of  the  common  people,  in  the  plaster  on 
the  outside  of  which  they  are  studded,  and  their 
pearly  iridescence  glitters  beautifully  in  the  sun- 
shine. 


GENUS.— PATELLA.* 

LIMPET. 

Generic  character.  Shell  univalve,  without  a 
regular  spire,  dilated,  conical,  entire,  concave 
beneath  in  proportion  as  it  is  convex  above. 

*  Plate  V.  figures  7,  8,  and  Plate  VI.  figure  1, 


PATELLA — LIMPET.  119 


OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  shells  of  this  genus  are  easily  distin- 
guished from  all  others  by  their  conical  form  and 
dilated  aperture  ;  but  they  are  subject  to  many 
peculiarities,  and  are  therefore  divided  into  se- 
veral natural  groups.  Some  are  remarkable  for 
an  internal  chamber  or  partition,  which  however 
varies  greatly  in  its  appearance.  In  the  Patellae, 
called  the  Slippers,  it  is  formed  by  the  columel- 
lar  lip,  which  is  straight  and  produced  into  a  flat 
horizontal  plate  extending  half  over  the  mouth 
of  the  shell.  In  others,  this  appendage  resem- 
bles a  cup  situated  at  the  apex  within  the  shell, 
and  the  Limpet  bearing  it  is  called  from  its  shape 
the  Cup  and  Saucer  Limpet.*  The  apex  of 
many  of  the  Patellae  is  perforated,!  and  this 
peculiarity  in  the  shell  is  connected  with  a  diffe- 
rent formation  of  the  animal,  whose  gills  are 
situated  near  the  holes  through  which  it  receives 
the  needful  supply  of  water.  In  some,  the  apex 
is  very  retuse ;  whilst  in  others  it  is  pointed  and 
elegantly  recurved.  J 

This  genus  is  peculiarly  interesting  to  those 
who  love  to  trace  the  regular,  but  almost  imper- 
ceptible gradations  existing  in  the  scale  of  na- 
ture. The  species  with  the  recurved  apex  seem 
to  form  the  link  which  connects  the  Patella?  with 
spiral  shells,  whilst  the  other  species,  where 

*  Plate  V.  figure  7.  t  Plate  V.  figure  8. 

|  Plate  VI.  figure  1. 


120  UNIVALVES. 

there  is  no  trace  of  any  volutions,  present  the 
intermediate  grade  between  them  and  the  shells 
entirely  destitute  of  spires. 

The  animal  of  the  Patella  has  a  large  fleshy 
proboscis,  and  two  tentacula,  with  the  eyes  on  a 
small  elevation  at  their  base  ;  the  mouth  has 
cartilaginous  plates  for  the  mastication  of  its 
food.  It  has  a  ventral  foot,  fleshy,  and  furnished 
with  numerous  muscular  filaments,  which  uni- 
ting on  the  upper  part  of  the  mantle,  form  a 
strong  muscle  by  which  the  body  adheres  to  the 
shell.  By  the  action  of  this  muscle,  the  shell 
can  be  brought  close  to  the  surface  to  which  the 
foot  adheres,  or  removed  to  a  distance.  By 
means  of  this  instrument,  the  animal,  when 
desirous  of  changing  its  situation,  sometimes 
effects  a  considerable  leap.  Its  locomotive 
powers,  however,  are  but  little  exercised  :  it 
appears  to  live  habitually  in  the  same  spot,  and 
rarely  to  perform  any  other  movement  than  that 
of  slightly  elevating  the  shell,  that  the  water  it 
breathes  may  reach  the  respiratory  organs. 
These  shells  are  generally  found  attached  to 
rocks,  sea-weed,  and  other  marine  substances, 
and  generally  in  such  numerous  clusters  that  the 
stones  appear  quite  studded  with  them ;  they 
adhere  with  considerable  tenacity,  and  are  not 
easily  displaced.  They  fix  themselves  thus  se- 
curely, by  applying  their  fleshy  foot  and  the  edge 
of  their  mantle  to  the  substance  on  which  they 
take  up  their  abode.  They  form  an  internal 
vacuum  by  the  contraction  of  their  muscles,  and 
the  pressure  of  the  external  air  then  keeps  them 


PATELLA — LIMPET.  121 

firmly  fixed  to  the  spot.  Thus  adhering  to  a 
solid  basis,  and  presenting  a  shell  whose  conical 
form  is  best  calculated  to  break  the  force  of  the 
rough  winds  and  dashing  waves,  this  little  ani- 
mal in  its  exposed  situation  exhibits  an  instance 
of  the  wise  provisions  of  the  Almighty  for  the 
protection  of  his  creatures.  This  genus  is  found 
in  all  parts  of  the  world,  but  abounds  particularly 
in  the  island  of  Cyprus.  Its  name  signifies  a 
little  dish,  an  appellation  suggested  by  its  form. 
The  animal  feeds  on  sea- weed  and  marine  vege- 
tables. The  manner  in  which  the  Limpet  at- 
taches itself  to  the  rocks  and  thus  seeks  shelter, 
is  beautifully  described  and  applied  in  the  follow- 
ing verses : 

« In  Nature's  all-instructive  book, 
Where  can  the  eye  of  reason  look, 
And  not  some  gainful  lesson  find 
To  guide,  and  fortify  the  mind  ? 
The  simple  shell  on  yonder  rock 
May  seem,  perchance,  this  book  to  mock-  • 
Approach  it  then,  and  learn  its  ways, 
And  learn  the  lesson  it  conveys. 
At  distance  viewed,  it  seems  to  lie 
On  its  rough  bed  so  carelessly, 
That  'twould  an  infant's  hand  obey 
Stretch'd  forth  to  seize  it  in  its  play  ; 
But  let  that  infant's  hand  draw  near, 
It  shrinks  with  quick,  instinctive  fear, 
And  clings  as  close  as  though  the  stone 
It  rests  upon,  and  it,  were  one  ; 
And  should  the  strongest  arm  endeavour 
The  Limpet  from  its  rock  to  sever, 
Tis  seen  its  loved  support  to  clasp 
With  such  tenacity  of  grasp, 
We  wonder  that  such  strength  should  dwell 
In  such  a  small  and  simple  shell ! 
And  is  not  this  a  lesson  worth 
The  study  of  the  sons  of  earth  ? 
Who  need  a  rock  so  much  as  we  ? 
Ah  !  who  to  such  a  rock  can  flee  ? 
A  rock  to  strengthen,  comfort,  aid, 
To  guard,  to  shelter,  and  to  shade, 
11 


122  UNIVALVES. 

A  rock,  whence  fruits  celestial  grow 

And  whence  refreshing  waters  flow — 

No  rock  is  like  this  rock  of  ours  ! 

Oh  then  if  you  have  learnt  your  pow'rs 

By  a  just  rule  to  estimate ; 

If  justly  you  can  calculate, 

How  great  your  need,  your  strength  how  frail, 

How  prone  your  best  resolves  to  fail, 

When  humble  caution  bids  you  fear 

A  moment  of  temptation  near, 

Let  wakeful  memory  recur 

To  this  your  simple  monitor, 

And  wisely  shun  the  trial's  shock 

By  clinging  closely  to  your  rock. 


PATELLA  GTOBCO. 
CANCELLATED  LIMPET. 

Specific  character.  Shell  ovate,  thick,  opaque, 
strongly  reticulated,*  some  of  the  longitudinal 
ridges  much  coarser  than  the  rest,  and  frequently 
tuberculated  by  the  crossing  of  the  transverse 
striae  ;  apex  lateral,  not  much  elevated,  truncated 
and  furnished  with  an  oblong  perforation ;  colour 
pale,  dull  brown,  or  yellowish  white ;  inside 
smooth,  white,  sometimes  rayed  with  dull  red  or 
brown  ;  margin  crenated,  sometimes  indented  ; 
length  about  three-quarters  of  an  inch,  breadth 
scarcely  half  an  inch,  height  a  quarter.  It  is 
rarely  found  on  the  British  coasts  of  a  superior 
size  ;  some  of  the  foreign  specimens  are  an  inch 
long. 

*  Reticulated,  crossed  like  net  work,  from  the  Latin  reticul 
MW,  a  small  net. 


PATELLA — HUNGARIAN   BONNET.      123 


PATELLA  Pettudda. 
BLUE-RAYED  LIMPET 

Specific  character.  Shell  sub-conical,  thin, 
pellucid,  smooth ;  summit  slightly  recurved, 
lateral ;  of  a  dusky  brown  colour,  rayed  with 
dotted  lines  of  the  brightest  azure  blue,  lines 
varying  in  number  from  three  to  seven  ;  length 
nearly  an  inch,  breadth  not  quite  three-quarters. 

This  species  is  common  in  many  parts  of  the 
Cornish  and  Devonshire  coasts  ;  it  is  never 
found  adhering  to  rocks,  but  is  picked  up  after 
storms,  having  been  thrown  on  shore  by  the  agi- 
tation of  the  waves,  along  with  the  sea-weed  to 
which  it  is  attached.  It  is  found  in  abundance 
at  Sandwich,  and  always  on  the  same  plant,  the 
stalk  of  which  the  animal  excavates,  probably 
for  food,  and  forms  a  cell,  in  which  are  some- 
times discovered  two  or  three  of  the  same  species 
together. 

PATELLA  Ungarica* 

HUNGARIAN  BONNET. 

Specific  character.  Shell  conical,  thin,  semi- 
transparent,  finely  striated  longitudinally,  and 
wrinkled  transversely  ;  summit  much  recurved, 

*  Plate  VI.  figure  1. 


124  UNIVALVES. 

and  ending  in  two  or  three  spiral  turns ;  it  is 
usually  covered  with  a  rough  epidermis  which 
projects  beyond  the  margin  and  forms  a  ciliated* 
border :  beneath,  the  colour  is  reddish,  the  in- 
side glassy  white,  or  flesh  colour ;  the  base,  which 
is  nearly  circular,  varies  from  one  to  two  inches 
in  diameter  ;  the  shell  is  rather  more  than  half 
as  high. 

This  species,  so  remarkable  for  its  elegant 
form,  is  found  on  the  western  shores  of  Britain, 
but  is  not  common. 


GENUS.— DENTALIUM.f 

TOOTH  OR  TUSK  SHELL 

Generic  character.  Shell  univalve,  resembling 
a  tooth,  straight  or  slightly  curved,  without  any 
internal  partition,  open  at  both  ends,  and  very 
gradually  tapering. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  shells  of  this  genus  are  easily  known  by 
their  very  simple  construction ;  they  all  more  or 
less  resemble  a  miniature  tusk,  and  4  the  name 

*  Ciliated,  bordered  with  a  fringe  like  eye-lashes,  from  the  Latin 
cilia,  an  eye-lash. 
f  Plate  VI.  figure  6 


DENTALIUM — TOOTH  SHELL.     125 

derived  from  the  Latin  dens,  a  tooth,  refers  to  this 
form.  There  are  but  few  species,  and  these 
vary  principally  in  external  appearance,  in  mag- 
nitude, in  the  degree  of  curvature,  and  in  the 
ribs  or  grooves  with  which  some  of  them  are 
ornamented.  One  of  the  largest,  called  Denta- 
lium  Elephantinum  is  often  three  or  four  inches 
long,  and  is  strongly  marked  with  longitudinal 
elevated  ribs.  One  species  is  so  minute  that  it 
is  scarcely  discernible  by  the  naked  eye,  and  re- 
sembles a  small  bristle. 

There  is  but  little  known  of  the  inhabitant  ot 
the  Dentalium  ;  some  naturalists  have  supposed 
it  to  be  free,  and  independent  of  its  shell,  but 
later  observations  have  led  to  the  discovery  of 
the  muscle  by  which  it  is  attached  to  its  abode, 
and  the  inhabitant  has  been  observed  to  shrink 
deeply  into  it  for  protection  from  [approaching 
danger. 

These  shells  are  found  principally  on  sandy 
shores,  sunk  more  or  less  deeply  in  the  ground, 
and  placed  in  a  vertical  position. 


DENTALIUM  Entails. 
COMMON  TOOTH  SHELL. 

Specific  character.  Shell  slightly  curved, 
slender,  tapering,  smooth,  glossy,  sometimes 
marked  with  a  few  circular  wrinkles  or  annu- 
lations,  colour  white  or  yellowish,  length  an 
inch  and  a  half ;  diameter  at  the  larger  end,  two 


126  UNIVALVES. 

tenths  of  an  inch,  and  one  fourth  as  much  at  the 
smaller  end. 

It  is  commonly  found  on  our  coasts,  particu- 
larly those  of  the  West  of  England.  The  ani- 
mal is  very  muscular,  its  shape  is  like  its  conical 
shell,  and  it  has  a  mantle  with  a  fleshy  collar 
through  which  it  can  protrude  its  head  and  foot. 
The  head  is  furnished  with  jaws,  and  lips  bear- 
ing teeth. 


GENUS.— SERPULA.* 


CREEPER   OR   WORM    SHELL. 

Generic  character.  Shell  univalve,  tubular, 
gradually  tapering,  usually  adhering ;  cavity  often 
interrupted  by  imperforate  dissepiments,!  at  ir- 
regular distances. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

These  shells  are  usually  found  in  very  irregu- 
lar and  diversified  groups  adhering  to  various 
marine  substances.  They  are  invariably  tubular, 
some  straight,  some  twisted ;  sometimes  they  are 
isolated  and  detached,  but  more  frequently  in 

*  Plate  VI.  figures  2,  3. 

t  Dissepiments  are  the  partitions  in  multilocular  shells:  fromthft 
Latin  sepes,  a  hedge,  and  dis,-a  prefix  signifying  division. 


SERPULA TUBULAR  CREEPER. 

clusters  consisting  of  hundreds  of  spiral  tubes 
curiously  interwoven ;  they  are  sometimes  curled 
into  a  spiral  form,  but  differ  materially  from  the 
convoluted  shells,  as  they  never  have  any  regular 
number  of  whorls,  or  any  appearance  indicating 
that  the  animal  is  directed  in  forming  these 
convolutions,  by  an  invariable  law.  The  name 
is  derived  from  the  Latin  serpo,  I  creep,  and 
well  designates  their  tortuous,*  vermiform^  ap- 
pearance. There  is  very  little  known  of  the 
animal.  The  Serpulse  abound  in  almost  all 
situations  that  are  at  times  covered  by  the  sea ; 
they  are  found  attached  to  various  marine  sub- 
stances, from  the  firmest  rock  and  the  sea-weed 
that  grows  upon  it,  to  sea-animals  the  most  rapid 
in  their  motions.  In  some  situations,  where 
they  are  not  subject  to  interruptions,  they  form 
patches  of  great  thickness  and  extent.  Some  of 
the  rocks  in  the  island  of  Gorre  are  covered  with 
a  crust  of  them  several  inches  thick,  and  more 
than  twenty  feet  square. 


SERPULA  Tubularia. 
TUBULAR  CREEPER. 

Specific  character.  Shell  taper,  opaque, 
slightly  wrinkled  transversely ;  the  smaller  end 
is  usually  convoluted  irregularly,  flexuous  or 
variously  twisted,  fixed ;  the  larger  end  frequently 

*  Tortuous,  from  the  Latin  tort  us,  twisted. 

t  Vermiform,  from  vermis,  a  worm,  and  forma,  a  form 


128  UNIVALVES. 

detached  for  half  its  length,  diameter  at  the  larger 
end  two-tenths  of  an  inch,  length  four  or  five 
inches. 

This  is  by  no  means  a  common  shell ;  it  is 
found  at  Tor  Cross,  Devonshire,  generally  on 
shells  ;  the  head  of  the  animal  inhabiting  it  is 
long,  white,  banded  with  pink  and  green,  and  has 
two  beatifully  feathered  tentacula,  originating 
from  a  single  stalk. 

SERPULA  Aquaria.* 
WATERING  POT. 

Specific  character.  Shell  taper,  straight,  with 
a  convex  disk  at  the  summit  perforated  so  as  to 
resemble  the  rose  of  a  watering  pot,  having  also 
a  radiated  border ;  the  colour  is  white,  with  a 
slight  tinge  of  pale  red  or  gray  ;  the  shell,  when 
perfect,  is  nearly  a  foot  long,  and  more  than  an 
inch  in  diameter  at  the  dilated  summit. 

This  most  singular  and  beautiftil  shell  is  rare  ; 
it  is  found  in  the  East  Indies.  It  bears  a  great 
resemblance  to  the  spout  and  rose  of  ^a  watering 
pot. 


GENUS.— TEREDO. 

SHIP  WORM. 

Generic  character.     \  Shell  tubular,  tapering, 
flexuous,  lodged  in  woody  substances,  with  two 

*  Plate  VI.  figure  3. 


TEREDO — SHIP  WORM.  129 

hemispherical  valves  anteriorly  truncated,  cover 
ing  the  head  of  the  animal,  and  two  others  of  a 
lanceolate  shape  near  the  extremity  of  the  tail. 


OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

Many  doubts  have  arisen  whether  this  genus 
ought  to  be  retained  among  the  univalve  shells. 
Some  naturalists  consider  the  two  hemispherical 
valves  as  the  primary  organs,  and  properly  the 
shell  of  the  animal,  as  it  adheres  to  them  by  a 
strong  muscle,  and  has  its  head  lodged  in  them, 
and  they  regard  the  tube  with  the  posterior 
valves  as  only  accessory.  The  use  of  the  tube 
is  to  secure  to  the  mollusca  a  lubricated  passage 
and  a  protection  against  the  rough  surfaces  of 
the  wood  in  which  it  resides.  It  is  formed  by  a 
calcareous  secretion,  which  appears  to  have  a 
solvent  power  over  the  resin,  and  even  over  the 
fibre  of  the  wood.  Unless  this  be  the  case  it  is 
difficult  to  account  for  the  fact,  that  these  crea- 
tures pierce  through  the  stoutest  oak  timber,  as 
they  do  not  seem  to  possess  any  organ  sufficiently 
strong  to  effect  such  perforations  by  a  simple 
mechanical  power.  On  examining  fresh  speci- 
mens, a  soft  pulpy  mass  of  a  chalky  appearance, 
which  hardens  when  exposed  to  the  air,  has  been 
discovered  at  the  opening  of  the  primary  valves, 
and  is  no  doubt  the  secretion  with  which  they 
lengthen  the  tube.  The  passage  is  open  at  both 
ends,  and  the  animal  does  not  in  any  way  adhere 


130  UNIVALVES. 

to  it ;  the  posterior  end  is  thickened  and  provided 
with  plates  which  contract  the  aperture,  and 
render  it  very  small :  this  part  is  always  even 
with  the  surface  perforated.  Near  the  extremity 
of  the  animal's  tail  are  situated  the  two  lanceo- 
late valves  which  seem  to  perform  the  office  of 
floodgates,  admitting  or  excluding  the  water  as 
necessity  may  require.  Linnaeus  considered 
that  the  valves  placed  at  both  ends,  were  of  the 
nature  of  opercula,  and  that  the  tube  was  the  shell 
of  the  animal,  which  he  consequently  placed 
among  the  univalves.  The  name  is  derived 
from  the  Greek  repsw  (tereo)  I  bore,  signifying 
the  supposed  manner  in  which  the  animal  effects 
a  settlement  in  different  substances. 

TEREDO  Navalis, 
COMMON  SHIP  WORM, 

Specific  character.  Shell  thin,  brittle,  straight, 
or  flexuous,  tapering  ;  inside  smooth,  pervious  ; 
the  smaller  end  thick  and  strong,  furnished  with 
plates  or  laminae,  which  contract  that  part  con- 
siderably, and  leave  a  very  small  opening  ;  the 
anterior  valves  attached  to  the  head  of  the  ani- 
mal are  of  a  hemispherical  form,  brittle,  thin, 
finely  striated,  and  covered  with  a  light  brown 
epidermis  ;  in  each  there  is  a  long  flat  curved 
tooth  projecting  inwards.  The  tube  is  white, 
sometimes  a  foot  long,  seldom  so  long  as  the 
animal ;  the  foreign  specimens  exceed  greatly 
in  size  those  found  in  England. 


TEREDO — COMMON  SHIP  WORM.         151 

This  singular  animal  has  proved  exceedingly 
destructive  to  our  shipping.  It  readily  enters 
the  stoutest  timbers,  and  ascends  the  sides  of  the 
loftiest  ships,  which  it  most  insidiously  destroys. 
When  the  hulk  of  a  ship  is  any  time  under  water, 
the  Teredines  appropriate  it  to  their  own  use,  and 
soon  commence  the  work  of  destruction. 

They  begin  with  the  softest  part,  and  at  first 
the  apertures  are  so  small  as  scarcely  to  be  per- 
ceptible. Their  manner  of  carrying  on  their 
labour  is  remarkable  ;  they  are  careful  never  to 
intrude  upon  the  habitation  of  a  neighbour,  and 
even  where  a  piece  of  wood  has  been  so  exca- 
vated as  to  resemble  a  honey-comb,  no  commu- 
nication or  passage  has  been  discovered  between 
the  perforations,  though  often  separated  only  by 
the  slightest  lamina  of  wood.  They  always  bore 
in  the  direction  of  the  grain  of  the  timber ;  if 
they  meet  in  their  course  with  another  shell  or 
a  knot,  they  make  a  turn ;  when  the  obstacle  is 
small,  they  wind  round  it,  and  then  proceed  on- 
wards, but  when  large,  rather  than  continue  any 
distance  across  the  grain,  they  make  a  short  turn 
back  in  the  form  a  siphon.  The  attacks  of  this 
insidious  enemy  have  not  been  confined  to  ship- 
ping ;  our  dock  yards  also  bear  sad  testimony  to 
their  work  of  devastation.  In  Holland,  where 
the  inroads  of  the  sea,  and  of  the  great  rivers  by 
which  that  country  is  intersected,  have  been  re- 
strained with  immense  labour  by  dykes,  the  Tere- 
dines have  proved  very  destructive,  piercing  and 
even  destroying  the  piles  which  sustained  them. 

Many  remarks  suggest  themselves  in  reading 


13£  UNIVALVES. 

the  history  of  this  animal.  How  insignificant 
often  are  the  means  employed  to  effect  the  most 
important  ends  ;  how  is  the  industry  of  years 
baffled  by  the  gradual  and  yet  certain  work  of  a 
little  worm.  We  might  at  first  be  disposed  to 
tax  the  wisdom  or  goodness  of  the  Almighty  in 
permitting  the  existence  of  an  animal  fitted  only 
for  what  appears  a  work  of  evil.  A  further 
acquaintance  with  the  subject,  will  bring  us  to  a 
very  different  conclusion.  Montague,  in  speak- 
ing of  them,  says,  "  that  the  Teredines  and  many 
aquatic  animals  were  created  by  the  Father  of 
the  universe  for  most  beneficent  purposes,  can- 
not be  disputed ;  for  though  they  may  seem  to 
impede,  and  even  to  destroy  the  operations  of 
man,  yet  they  are  of  such  importance  in  the  great 
scale  of  nature,  that  it  has  been  observed,  and  it 
would  not  be  difficult  to  prove,  that  we  should 
feel  the  want  of  one  or  two  species  of  larger 
quadrupeds  much  less  than  one  or  two  species  of 
these  despicable  looking  animals.  The  im- 
mense trees  and  forests  of  tropical  countries, 
either  overthrown  by  tornadoes,  or  partially  de- 
stroyed by  insects,  and  then  carried  by  rapid 
torrents  into  the  rivers,  would  not  only  choke 
them  up,  but  even  endanger  the  navigation  of  the 
neighbouring  seas,  were  it  not  for  these  small 
yet  powerful  agents  of  dissolution.  Nothing 
can  more  plainly  demonstrate  the  power  of  an 
all-wise  ruler  of  the  universe  than  the  work 
assigned  to  these  animals,  whose  business  it  is, 
to  hasten  the  destruction  of  all  useless  matter." 


SABELLA.  133 

GENUS.— -SABELLA. 

SABELLA. 

Generic  character.  Shell  tubular,  composed 
of  sandy  or  calcareous  particles,  and  sometimes 
fragments  of  shells  agglutinated  together,  and 
united  to  a  membranaceous  sheath  by  a  cement. 

• 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

This  genus  is  now  very  generally  dismissed 
from  the  class  of  Testaceous  Mollusca,  as  the 
tubes  in;  which  the  animals  are  enclosed  are 
more  or  less  composed  of  extraneous  matter, 
and  not  of  a  testaceous  secretion  prepared  by  the 
animal  from  its  own  body,  and  forming  a  com- 
pact solid  substance,  which  is  the  true  character 
of  a  shell.  Its  best  claim  to  retain  its  position, 
is,  that  the  mould  to  which  the  various  particles 
are  attached,  is  really  a  calcareous  and  not  an 
animal  substance.  The  name  of  the  genus  is 
taken  from  the  Latin,  sabulum,  fine  gravel  or 
sand,  of  which  material  their  habitations  most 
usually  consist. 


134  UNIVALVES. 

GENUS.— NAUTILUS.* 


SAILOR. 

Generic  character.  Shell  univalve,  spirally 
convoluted,  smooth,  multilocular ;  f  chambers 
perforated  and  connected  by  a  siphunculus  or 
pipe  ;  the  dissepiments  are  convex  inwardly,  the 
chambers  gradually  increase  in  size  from  tlie 
apex.  The  animal  resides  in  the  latter. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  Nautili  differ  much  in  size  ;  some  being 
too  minute  to  be  observed  by  the  naked  eye, 
while  others  are  a  foot  in  diameter.  In  some 
the  whorls  are  contiguous ;  in  others  they  are  de- 
tached. The  tube  which  connects  the  chambers 
is  supposed  to  admit  either  air  or  water,  as  the 
animal  requires.  When  the  shell  is  stationed  at 
the  bottom  of  the  sea,  the  siphon  is  filled  with 
aqueous  fluids ;  by  excluding  these  the  gravity 
of  the  shell  is  diminished,  and  it  rises  in  conse- 
quence to  the  surface.  When  on  the  contrary 
the  animal  is  inclined  to  descend,  it  contracts 
itself  within  its  boat,  draws  in  water,  and  imme- 
diately disappears.  Though  capable  of  floating 

*  Plate  VI.  figure  4. 

f  Multilocular,  having  many  little  chambers,  from  the  Latin 
words,  multus,  many,  and  loculum,  a  little  chamber. 


NAUTILUS SAILOR.  135 

on.tne  surface  of  the  sea,  it  is  often  found  re- 
versed, and  like  a  snail  bearing  its  house  upon 
its  back.  The  name  is  derived  from  the  Greek 
word  vaunAos  (nautilos)  a  sailor. 

The  animals  inhabiting  the  shells  of  this  and 
the  following  genus  vary  considerably  from  the 
other  Mollusca ;  they  are  called  Cephalopodes,* 
(footed  at  the  head,)  because  their  heads  are 
surrounded  by  arms  or  teritacula.  Their  bodies 
are  fleshy,  like  the  other  Mollusca,  and  the 
posterior  portion  is  contained  in  the  mantle  of 
the  animal.  Their  mouth  is  vertical  and  armed 
with  two  corneous  mandibles  resembling  the 
beak  of  a  parrot,  They  live  in  the  sea,  are 
carnivorous,  and  feed  on  crabs  and  other  marine 
animals.  The  position  of  their  arms  enables 
them  to  seize  their  prey,  and  bring  it  to  their 
mouth.  The  Cephalopodes  which  form  a  mul- 
tilocular  shell,  instead  of  being  enclosed  within 
their  shell,  envelop  it  so  as  only  to  leave  a  small 
portion  visible  :  a  tendinous  thread  issuing  from 
the  extremity  of  the  body  appears  to  attach  it  to 
the  shell,  and  probably  has  some  connexion  with 
the  siphunculus. 

As  in  the  genus  Serpula  we  observed  how 
extensive  a  work  of  destruction  is  carried  on  by 
a  little  worm,  here  we  have  to  notice  the  reverse 
of  that  fact.  A  very  small  species  of  the  Mul- 
tilocular  Cephalopodes,  called  Miliola,  (being 
about  the  size  of  a  grain  of  millet,)  exhibits  the 
power  of  reproduction  in  an  equally  astonishing 

*  Cephalopodea.     Having  feet  on  the  head,  from  the  Greek 
ephale)  a  head,  and  *o<J«s  (podes)  feet. 


136  UNIVALVES. 

degree.  Around  Paris  these  shells  are  found  in 
the  fossil  state  in  such  prodigious  quantities,  that 
small  as  they  are,  they  form  the  principal  part  of 
the  immense  masses  of  stone  which  constitute 
some  of  the  quarries. 

NAUTILUS  Pompilius* 
LARGE  CHAMBERED  NAUTILUS. 

Specific  character.  Shell  with  an  involuted 
and  concealed  spire,  smooth ;  aperture  cordate  ; 
colour  whitish,  with  waved  streaks  of  reddish  or 
yellowish  brown,  pearly  within. 

This  beautiful  shell  is  often  converted  by  the 
inhabitants  of  the  East  into  a  drinking  cup ;  on 
the  surface  they  engrave  various  ornaments  and 
devices. 

NAUTILUS  Spirula. 
CROSIER  NAUTILUS. 

Specific  character.  Shell  thin,  brittle,  trans- 
parent, with  five  cylindrical  detached  whorls 
divided  into  numerous  compartments ;  distin- 
guished on  the  outside  by  a  depressed  circular 
line  ;  the  last  volution  takes  a  straight  direction, 
and  is  remote  from  the  adjoining  one  ;  aperture 
orbicular,  pearly  within ;  chambers  separated  by 
their  pearly  plates,  but  communicating  with  each 

*  Plate  VI.  figure  4. 


ARGONAUT  A PAPER  SAILOR.  137 

other  by  a  small  siphunculus ;  white  or  cream 
colour ;  the  shell  when  perfect  about  an  inch 
in  diameter. 

This  shell  is  so  exceedingly  brittle  that  perfect 
specimens  are  very  rare.  The  last  chamber, 
which  the  animal  inhabits,  is  a  straight  cylinder, 
but  it  is  so  fragile  that  a  vestige  of  it  is  seldom 
to  be  met  with.  In  the  broken  state  in  which 
these  shells  are  found,  they  resemble  a  ram's 
horn,  and  so  they  have  been  described,  but  when 
complete  they  have  more  the  appearance  of  the 
crosier.  The  mouth  of  the  animal  is  surrounded 
by  ten  arms,  two  being  longer  than  the  others. 
This  Nautilus  is  found  in  great  numbers  in  the 
West  Indies. 


GENUS.— ARGONAUTA.* 


PAPER  SAILOR. 

Generic  character.  Shell  univale,  involuted, 
the  last  turn  very  large,  having  a  double  tuber- 
culated  carina,  thin,  transparent,  delicate,  uni- 
locular;  aperture  cordate,  entire,  contracted. 
This  shell  has  much  the  appearance  of  being 
composed  of  two  pieces  united  by  the  keel,  and 
seems  to  be  the  link  between  the  univalve  ancl 
bivalve  shells. 


*  Plate  VI.  figure  5. 

12* 


138  UNIVALVES. 


OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  animal  inhabiting  these  elegant  shells  is 
soft  and  fleshy,  having  a  large  portion  of  its  body 
enveloped  in  the  mantle ;  its  head  is  furnished 
with  two  eyes,  and  round  its  mouth  are  arranged 
like  rays  eight  elongated  and  pointed  tentacula 
or  arms.  Two  of  these  have  a  thin  membrane 
extending  more  than  half  their  length.  This 
singular  appendage  the  animal  can  expand  or 
draw  in  at  pleasure.  The  shell  is  of  a  thin 
paperlike  substance,  resembling  in  form  a  kind 
of  boat.  Few  objects  can  be  conceived  more 
interesting  than  this  beautiful  animal  seated  in 
its  pearly  little  vessel  ;  two  tentacula  erected, 
with  their  membrane  unfurled  like  a  sail,  whilst 
the  remaining  six,  suspended  over  the  sides 
of  the  little  bark,  perform  the  office  of  oars. 
When  wafted  by  propitious  gales,  it  calmly  rides 
over  the  waves  ;  but  should  a  storm  threaten,  or 
an  enemy  approach,  it  precipitately  hauls  in  its 
tackle,  shrinks  into  its  shell,  and  drawing  in 
water  to  add  to  its  weight,  seeks  protection  in  the 
depths  of  the  sea  :  the  danger  over,  it  diminishes 
the  gravity  of  its  shell  by  ejecting  the  water,  and 
rises  again  to  the  surface. 

It  has  long  been  a  doubt  whether  this  animal 
is  the  true  inhabitant  of  the  Argonauta,  and  it  is 
supposed  by  many  naturalists  to  be  one  of  the 
eight-armed  Sepia  or  Cuttle-fish,  which,  like  the 


ARGONAUTA PAPER  SAILOR.  139 

Hermit  Crab,  having  destroyed  the  original 
fabricator  of  the  shell,  takes  possession  of  the 
vacated  tenement. 

How  does  this  little  animal  verify  the  words 
of  the  Psalmist,  "  They  that  go  down  to  the  sea 
in  ships,  that  do  business  in  great  waters,  they 
see  the  works  of  the  Lord,  and  his  wonders  in 
the  deep."  Ps.  cvii.  23,  24. 

The  art  of  navigation,  in  the  imagination  of 
the  poet,  owed  its  origin  to  the  expert  manage- 
ment of  these  little  instinctive  sailors,  whilst 
their  shell  suggested,  the  first  idea  of  a  vessel. 
The  name  Argonauta  is  derived  from  vavr$ 
(nautes)  a  sailor ;  and  Argo,  the  name  of  the 
ship  in  which  Jason  made  his  memorable  voyage 
with  his  companions,  the  Argonauts. 


ARGONAUTA  Argo* 
PAPER  NAUTILUS. 

Specific  character.  Shell  having  a  narrow 
keel  sharply  toothed  on  both  sides ;  sides  flat, 
with  undulated  forked  ribs,  extremely  thin  and 
brittle ;  colour  white,  teeth  of  the  keel  brown 
towards  the  apex.  Inhabits  the  Mediterranean 
and  Indian  Ocean. 

*  Plate  VI.  figure  5, 


140  UNIVALVES. 


QUESTIONS  ON  THE  UNIVALVE 
SHELLS. 

1.  What  are  the  parts  of  an  univalve  shell  ? 

2.  Give  a  description  of  each  part,  with  the 
derivation  of  the  terms. 

3.  How  is  the  generic  character  of  univalve 
shells  determined  1 

4.  How  is  the  specific  character  of  univalve 
shells  determined  ? 

5.  Give  a  list  of  the  genera  of  univalve  shells? 

6.  Name  those  which  have  regular  spires. 

7.  Name  those  without  spires. 

8.  Which  shells  seem  to  connect  the  shells 
with  spires,  and  those  without  1 

9.  What  shells  have  longitudinal  apertures  ? 

10.  Which  shells  are  canaliculated,  and  which 
entire  ? 

11.  Which  of  the  univalve  shells  resemble 
each  other?     Describe  their  points  of  resem- 
blance, and  also  in  what  respect  they  differ. 

12.  In  what  respect  do  the  shells  of  warm 
climates  differ  from  those  of  colder  regions  ? 

13.  What  is  the  generic  character  of  the 
Cone  ?  and  what  its  distinguishing  mark? 

14.  What  remarkable  instinct  is  exhibited  by 
the  animal  of  the  Cone  ? 

15.  Where  are  Cones  found? 

16.  What  is  the  generic  character  of  the  Cy- 
praea,  and  what  its  most  distinguishing  mark  ? 

17.  What  is  there  remarkable  in  the  manner 


QUESTIONS  ON  UNIVALVES.  141 

in  which  the  shell  of  the  Cypraea  is  formed,  and 
increased  in  size  ? 

18.  What  is  the  generic  character  of   the 
Bulla,  and  what  its  distinguishing  mark  ? 

19.  What  remarkable  organ  is  possessed  by 
the  animal  of  the  Bulla?     Describe  the  organ 
and  its  use. 

20.  Describe  the  peculiar  habits  of  the  animal 
of  Bulla  Fontinalis. 

21.  Give  the  generic  character  of  the  Voluta, 
and  its  distinguishing  mark. 

22.  Into  what  different  families  is  the  Voluta 
subdivided,  and  how  are  they  distinguished  ? 

23.  Wrhat  is  the  generic  character  of  the  Buc- 
cinum,  and  its  distinguishing  marks  1 

24.  Describe  the  different  groups  into  which 
the  genus  Buccinum  has  been  subdivided. 

25.  What  is  the  origin  of  the  name  Bucci- 
num? 

26.  What  use  has  been  made  of  the  Bucci- 
num? 

27.  Describe  the  habits  of  the  Hermit  Crab. 

28.  What  is  the  generic  character  of  Strom- 
bus,  and  what  its  most  characteristic  mark  ? 

29.  Describe  how  the  shells  called  Alatae,  or 
winged  Strombi,  are  increased  at  the  different 
stages  of  the  animal's  growth. 

30.  What  is  the  generic   character  of  the 
Murex,  and  what  is  its  distinguishing  mark  ? 

31.  Describe  the  different  families  into  which 
the  genus  Murex  is  subdivided,  and  mention 
how  the  forms  of  these  shells  are  connected  with 
the  peculiar  habits  of  their  animals. 


142  UNIVALVES. 

32.  Which  are  the  shells  anciently   called 
Purpuras  ? 

33.  Describe  the  manner  in  which  the  purple 
dye   was  obtained    and  prepared,  the  different 
uses  to  which  it  was  applied,  and  the  circum- 
stance supposed  to  have  led  to  its  discovery. 

34.  What  is  the  generic  character  of  the 
Trochus,  and  what  its  most  distinguishing  mark  ] 

35.  Describe  a  remarkable  peculiarity  in  one 
of  the  species  of  Trochus. 

36.  What  is  the  generic  character  of  Turbo, 
and  its  distinguishing  mark  ? 

37.  Which  species  of  Turbo  is  remarkable, 
and  on  what  account  ? 

38.  What  is  the  generic  character  of  Helix, 
and   by    what   mark    is    it   particularly  distin- 
guished 1 

39.  What  variety  of  form  is  displayed  in  the 
Helices  ? 

40.  Detail  the  interesting  facts   connected 
with  the  natural  history  of  the  Helix. 

41.  How  does  the  Helix  lanthina  display  the 
compensatory  providence  of  God  1 

42.  What  is  the  generic  character  of  the  Ne- 
rita,  and  by  what  mark  is  it  readily  known  ? 

43.  What  is  the  generic  character  of  the 
Haliotis,  and  what  its  distinguishing  mark  ? 

44.  What  is  known  of  the  habits  of  the  animal 
inhabiting  the  Haliotis  ? 

45.  What  is  the  generic  character  of  the  Pa- 
tella, and  what  its  most  distinguishing  mark  1 

46.  Describe  the  different  groups  into  which 
the  genus  Patella  is  subdivided  ? 


QUESTIONS  ON  UNIVALVES.  143 

47.  What  is  there  particularly  interesting  in 
the  natural  history  of  the  Limpet  ? 

48.  What  lesson  has  the  poet  drawn  from  their 
natural  history  ? 

49.  What  is  the  generic  character  of  the  Den- 
talium,  and  what  its  distinguishing  mark  ? 

50.  What  is  the  generic  character  of  the  Ser- 
pula,  and  its  distinguishing  mark  ? 

51.  In  what  situations  are    Serpulae  found, 
and  under  what  circumstances  ? 

52.  What  is  the  generic  character  of  the 
Teredo  ? 

53.  What  are  the  reasons  for  and  against  re- 
taining the  Teredo  among  the  univalve  shells  1 

54.  Describe  the  work  of  the  Teredo  Na- 
valis. 

55.  What  is  the  generic  character  of  the  Sa- 
bella  ? 

56.  What  is  the  generic  character  of  the  Nau- 
tilus, and  its  distinguishing  mark  1 

57.  What  kind  of  animal  inhabits  the  Nau- 
tilus ? 

58.  What  is  there  remarkable  in  the  natural 
history  of  the  Nautilus  1 

59.  What  is  the,  generic    character  of  the 
Argonauta  ? 

60.  What  position  does  the  Argonauta  appear 
to  occupy  in  the  chain  of  nature  1 

61.  Describe  the  habits  of  the  animal  inhabi- 
ting the  Argonauta. 


BIVALVES.* 

The  shells  belonging  to  this  class  are  com- 
posed of  two  pieces  united  by  an  elastic  horny 
ligament  :|  this  part  where  the  valves  are  joined 
together,  is  called  the  cardo^  or  hinge,  and  cor- 
responds in  position  with  the  back  of  the  animal : 
it  is  either  plain  or  furnished  with  teeth.  The 
ligament  serves  not  only  to  connect  the  valves, 
but  also  to  open  them,  and  is  either  external  or 
internal.  The  muscle  or  muscles  by  which  the 
animal  is  attached  to  the  shell  keep  it  closed  : 
when  these  are  relaxed,  the  ligament,  which  was 
either  in  a  state  of  tension  or  compression  ac- 
cording as  it  was  either  external  or  internal,  by 
its  efforts  to  recover  its  position  opens  the  valves. 
If  the  two  valves  are  quite  alike,  the  shell  is  said 
to  be  equivalve;§  if  they  differ  in  form  or  size,  it 
is  called  inequivalve.  If  the  sides  of  the  valve 
are  symmetrical,  the  valve  is  said  to  be  equilate- 
ral;^ if  they  are  not,  it  is  said  to  be  inequilateral. 

The  animals  belonging  to  the  Bivalve  shells 
are  acephalous  mollusca  having  no  distinct 
head  ;  they  have  no  eyes,  and  the  mouth,  which 
is  hidden  under  the  mantle,  is  only  a  simple 

*  For  the  parts  of  a  Bivalve  shell,  see  Plate  I. 

t  Ligament,  a  substance  which  serves  to  bind  things  together, 
from  the  Latin,  lig  are,  to  bind. 

|  Cardo  is  the  Latin  word  for  a  hinge. 

§  Equivalve,  having  equal  valves,  from  Latin,  equ  us,  equa^ 
and  valve. 

||  Equilateral,  having  equal  sides,  from  Latin,  equ  usy  equal, 
ana  latera,  sides. 


BIVALVES.  145 

opening  for  the  reception  of  food,  without  pro- 
boscis, jaws  or  any  hard  parts  fitted  for  mastica- 
tion. This  mouth  is  surrounded  by  four  flat- 
tened moveable  expansions,  which  partake  of  the 
nature  of  tentacula.  The  branchice,*  or  gills, 
consist  of  two  leaves  or  expansions  on  each  side, 
and  extend  the  length  of  the  body.  The  mantle 
is  large,  sometimes  it  is  quite  open,  and  bor- 
dered with  contractile,  irritabje  filaments  :  in 
some  instances  it  is  joined  in  front,  forming  tu- 
bular elongations,  called  siphons,  which  conduct 
the  water  to  the  mouth  and  branchise.  The  mus- 
cles are  generally  very  thick  and  strong,  and 
hard  at  the  place  of  attachment  to  the  shell  ; 
those  which  close  the  valves  are  called  the  ad- 
ductor^ muscles.  Many  species  have  not  the 
power  of  locomotion,  but  are  immoveably  ce- 
mented to  rocks  or  stones  :  a  few  are  attached 
by  a  cartilaginous  ligament,  others  by  a  byssus. 
These  mollusca  have  no  ventral  foot  similar  to 
that  possessed  by  some  of  the  cephalous  mol- 
lusca; but  some  have  a  muscular  substance 
usually  tongue-shaped  and  capable  of  conside- 
rable elongation.  This  organ  enables  them  to 
creep,  or  to  effect  a  kind  of  leap,  by  which  they 
change  the  position  of  their  shells  ;  sometimes 
it  is  transformed  into  a  paw,  and  sometimes  it 
is  employed  to  fix  the  silky  filaments  of  a  byssus. 
None  of  the  Bivalves  are  terrestrial  shells,  some 
few  are  fluviatile.  The  generic  character  of  the 

*  Branchiae,  is  derived  from  the  Greek,  /Jpay#ia  (branchia)  the 
gills  of  fish. 

•j"  Adductor,  is  derived  from  addu  co,  I  bring  together. 
13 


146  BIVALVES. 

Bivalves  is  principally  derived  from  the  formation 
of  the  hinge,  and  the  general  appearance  of  the 
shell. 


PARTS  OF  A  BIVALVE  SHELL. 

The  valves. 

The  cardo  or  hinge,  the  part  where  the  valves 
are  united. 

The  beaks  or  apices,  the  points  of  the  valves 
near  the  hinge. 

The  base,  the  part  of  the  shell  opposite  the 
beaks. 

The  umbones  or  bosses,  the  swelled  parts  near 
the  beaks. 

The  ligament. 

The  margin  of  valves. 

The  area  or  anterior  slope,  the  margin  of  the 
valves  near  the  ligament. 

The  areola  or  posterior  slope,  the  margin  of 
the  valves,  the  other  side  of  the  ligament. 

The  cavity. 

The  disk,  the  convex  part  of  the  valves  be- 
tween the  umbones  and  margin. 

The  length,  the  direction  of  the  shell  from  the 
beak  to  the  base. 

The  breadth,  the  direction  at  right  angles  with 
the  length. 

The  auriuclcz*  or  ears,  small  appendages 
laced  at  the  side  of  the  hinge. 

*  Auricula,  a  small  ear  ;  the  diminutive  of  the  Latin  auris,  an 
ear. 


MYA GAPER.  147 

The  circumference. 

The  muscular  impressions,  marks  in  the  inside 
of  the  shell  made  by  the  adhesion  of  the  adduc- 
tor muscles. 

The  right  valve,  the  valve  nearest  to  the  right 
hand,  when  the  shell  is  placed  on  its  base  with 
the  area  opposite  to  the  person  looking  at  it. 

The  left  valve. 

The  teeth,  pointed  protuberances  at  the  hinge. 

The  cardinal  teeth,  the  central  teeth,  or  those 
near  the  centre  of  the  hinge. 

The  lateral  teeth,  the  teeth  near  the  sides. 


GENUS.— MYA.* 

GAPER. 

Generic  character.  Shell  bivalve,  equivalve, 
inequilateral,  sometimes  gaping  at  one  end, 
sometimes  at  both ;  shape  suboval,  broader  than 
it  is  long  ;  generally  smooth,  or  only  slightly 
striated  ;  hinge  with  a  thick,  strong,  patulous,^ 
or  spoon-shaped  tooth,  sometimes  inserted  into 
the  opposite  valve. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  points  of  generic  resemblance  in  the  Myae 
are  wanting  in  many  of  the  species.  The  coarse 

*  Plate  VII.  fig.  1 ,  2. 

t  Patulous,  lying  open,  spreading,  from  the  Latin,  pat  ere,  to 
Jie  open. 


148  BIVALVES, 

large  tooth  is  the  characteristic  of  the  hinge,  but 
sometimes  it  is  not  more  than  a  thickened  callo- 
sity.* Some  species  are  altogether  destitute  of 
teeth  ;  these  have  a  rounded  cavity  for  the  re- 
ception of  the  cartilage.  The  gaping  of  the 
valves  is  another  distinguishing  feature,  but  it 
does  not  always  occur.  In  form  also  the  shells 
differ  considerably  ;  some  are  oblong  and  trun- 
cated, as  if  a  part  of  the  shell  had  been  cut  off ; 
others  are  orbicular,  and  many  are  angular  from 
the  addition  of  ears  at  the  hinge.  The  Myae  are 
generally  covered  with  a  thick  brown  or  green 
epidermis  ;  when  this  is  removed,  the  surface 
exhibits  a  beautiful  iridescent  mother-of-pearl 
lustre.  Some  of  the  species  grow  to  a  great  size ; 
others  are  remarkable  for  their  thick,  solid, 
and  substantial  shells,  and  have  in  consequence 
been  formed  into  a  distinct  genus,  called  Unio. 
Many  of  the  Mollusca  of  this  genus  burrow  in 
the  sand  or  mud,  boring  a  channel  through  which 
they  thrust  a  contracted  trunk  inclosing  two 
tubes.  The  My®  furnish  food  not  only  for  man, 
but  also  for  many  aquatic  birds. 

MYA  Truncata.] 
TRUNCATED  GAPER. 

Specific  character.     Shell  ovate,  convex,  trun- 
cated at  the  anterior  end,  where  it  gapes  consi- 

*  Callosity,  hardness  of  skin  or  flesh,  from  Latin  call  MS,  which 
has  the  same  signification  ;  hence  our  English  word  callous. 
f  Plate  VII.  figure  2. 


MYA GAPER.  149 

derably,  curved  at  the  areola,  wrinkled  trans- 
versely, and  covered  with  a  brownish  yellow 
tough  epidermis,  extending  an  inch  or  two  be- 
yond the  gaping  end,  like  a  thick  membrane, 
through  which  the  animal  protrudes  its  tube ; 
hinge  with  a  rounded  tooth  projecting  forwards  ; 
inside  white ;  length  from  one  to  two  inches ; 
breadth  from  two  to  three. 

These  shells  inhabit  the  sand  or  gravel  about 
low  water  mark  on  most  of  the  northern  coasts 
of  Europe.  In  Greenland  their  mollusca  are 
the  food  of  man  and  other  animals.  When  taken 
alive,  the  epidermis  of  the  shell  is  found  joined 
to  the  tube  or  proboscis  of  the  animal,  having 
become  a  thick,  tough,  coriaceous*  skin  for  its 
protection.  The  animal  is  capable  of  extending 
this  tube  to  the  distance  of  nine  or  ten  inches, 
and  of  contracting  it  to  about  three,  but  cannot 
withdraw  it  entirely  into  the  shell. 

MYA  Marga  atifera. 
PEARL-BEARING  OYSTER. 

Specific  character.  Shell  strong,  ponderous, 
thick  ;  shape  ovate,  oblong,  front  compressed, 
margin  a  little  contracted  in  the  middle,  giving 
a  somewhat  curved  outline  to  the  circumference ; 
hinge  consisting  of  a  cardinal  tooth  in  one  valve, 
which  is  thick,  obtusely  conical,  and  locking  into 

*  Coriaceous,  like  leather,  derived  from  the  Latin  con  wm,  skin, 
leather. 

13* 


150  BIVALVES. 

a  bifurcated*  tooth  in  the  other  valve ;  shell 
about  two  inches  long,  and  four  broad ;  covered 
with  a  black  epidermis  decorticated^  at  the  um- 
bones  ;  inside  of  a  greenish  pearly  hue. 

This  shell  is  one  of  a  very  interesting  group, 
now  formed  into  a  distinct  genus  and  called 
Unio.  It  inhabits  only  rocky  torrents,  and  the 
precipitous  streams  of  mountainous  districts. 
Many  are  found  in  the  cataracts  and  rapid  rivers 
of  America,  and  by  their  solid  and  thick  shells 
manifest  the  providential  care  that  fitted  them 
for  the  dangerous  spots  they  occupy.  When  we 
look  at  the  ponderous  Mya  driven  by  the  power- 
ful torrent,  and  compare  it  with  the  light  and  de- 
licate lanthina,  borne  gently  on  the  surface  of  the 
waves,  shall  we  coldly  attribute  such  adaptation 
to  circumstances  or  the  blind  dealing  of  chance, 
and  not  rather  delight  to  recognise  the  benefi- 
cent wisdom  of  our  heavenly  Father,  pervading 
all  his  works,  and  suiting  each  to  the  place  he 
assigns  it  1 

The  Mya  Margaratifera  is  found  in  several  of 
our  rivers,  particularly  those  of  Wales  ;  also  in 
Ireland,  where  the  peasantry  use  the  valves  as 
spoons.  This  species  has  long  been  celebrated 
for  producing  pearls  of  a  good  colour,  and  some- 
times of  a  considerable  size.  These  ornaments 
appear  to  be  exclusively  the  production  of  the 
Bivalve  testacea,  and  are  found  only  in  the  shells 


*  Bifurcated,  having  a  fork  of  two  teeth :  from  the  Latin  bis, 
twice  ;  and  furca,  a  fork. 

t  Decorticated,  having  the  bark  or  outer  skin  taken  off  j  from  the 
Latin  de,  off :  and  cortex,  the  bark  of  a  tree. 


SOLEN RAZOR  SHELL.       151 

which  have  a  coating  of  mother-of-pearl  in  the 
inside  of  their  valves.  Pearls  are  said  to  be 
produced  by  a  disease  of  the  animal,  occasion- 
ing a  partial  secretion  of  the  substance,  which 
forms  the  inner  coating  of  the  shell.  The  Bri- 
tish islands,  especially  Ireland,  have  been  noted 
for  their  pearl  fisheries.  The  Con  way  was  for- 
merly celebrated  for  this  production  :  a  large 
one  which  was  taken  in  that  river,  and  presented 
by  Sir  Richard  Wynne  the  chamberlain,  to 
Catherine  the  consort  of  Charles  II.  is  said  still 
to  adorn  the  British  crown. 


GENUS.— SOLEN.* 

RAZOR  SHELL. 

Generic  character.  Shell  bivalve,  equivalve, 
oblong,  transversely  elongated,  gaping  at  both 
ends  ;  hinge  has  a  subulate,  reflected  tooth, 
sometimes  double,  not  inserted  into  the  opposite 
valve.  Most  of  the  shells  are  brittle  ;  some 
have  an  internal  rib  extending  from  the  hinge  to 
the  opposite  margin. 

*  Plate^VIL  fig.  3,  4,  5. 


152  BIVALVES. 


OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

There  is  generally  but  little  difficulty  in  deter- 
mining the  Solenes  :  they  are  recognised  by 
their  oblong  form,  their  disproportionate  breadth 
and  their  gaping  at  both  extremities.  A  few  of 
the  species,  however,  are  oval,  and  these  have 
their  hinge  nearly  central.* 

The  history  of  this  genus  affords  various  in- 
stances of  ingenuity  in  the  application  of  very 
simple  means.  The  animal  is  furnished  with  a 
long  pliable  cylindrical  leg ;  when  he  wishes  to 
bore  a  hole  for  his  residence  he  extends  this  in- 
strument from  the  inferior  end  of  the  shell,  using 
it  as  a  pointed  shovel  to  excavate  the  sand. 
When  the  tunnel  is  partly  formed,  the  animal 
advances  the  leg  a  little  farther,  fixes  it  by  its 
point  as  a  hook  in  the  ground,  and  using  this  as 
a  fulcrum  descends  in  safety,  continuing  the 
operation  till  the  shell  is  buried  about  two  inches 
under  ground.  When  the  animal  wishes  to  re- 
gain the  surface,  the  leg  is  rolled  up  into  a  sphe- 
rical form,  and  stretched  very  tight ;  by  means 
of  the  ball  thus  formed,  the  little  creature  is  pre- 
served from  slipping  backward,  while  by  the 
action  of  its  muscular  power,  it  throws  the  shell 
forward.  The  peculiar  habits  of  the  Solen  ren- 
der no  other  than  perpendicular  motion  neces- 
sary to  it,  and  therefore  while  the  form  of  its 
shell,  and  the  powers  with  which  it  is  gifted,  are 

*  Plate  VII.  fig.  5. 


SOLEN RAZOR  SHELL.       153 

admirably  calculated  for  movement  in  this  direc- 
tion, it  is  unable  to  advance  horizontally.  It  re- 
quires a  safe  retreat  and  a  supply  of  food  ;  the 
former  it  obtains  by  withdrawing  into  its  recess, 
and  the  latter  by  ascending  its  channel  when  the 
tide  comes  in  and  brings  the  little  marine  insects 
which  form  its  food.  The  retreat  of  the  Solen 
is  marked  by  a  small  depression  on  the  sand ; 
sometimes  the  shells  are  dug  out  by  the  fisher- 
men, but  as  this  is  a  laborious  employment,  they 
are  often  entrapped  by  stratagem.  For  this 
purpose,  at  the  reflux  of  the  tide,  when  the  men 
can  approach  them,  a  little  salt  is  placed  round 
their  perforations,  which  melting,  is  mistaken  by 
the  animal  for  the  return  of  the  tide,  and  thus 
decoyed  they  elevate  themselves  in  the  expecta- 
tion of  finding  their  prey.  So  rapid,  however, 
are  their  actions  that  great  dexterity  is  requisite 
to  catch  them,  before  they  again  sink  into  their 
retreat,  and  if  they  are  successful  in  escaping, 
they  are  not  easily  tempted  again  to  the  surface. 
In  many  places  this  animal  is  valued  as  food. 
The  name  Solen,  is  derived  from  the  Greek 
ffwAw  (solen)  a  tube.  The  French,  in  allusion 
to  the  shape  of  the  shells,  call  them  manches  de 
couteaux. 

SOLEN  Siliqua* 
POD  RAZOR  SHELL. 

Specific  character.     Shell  straight,  subcylin- 
drical,  truncated  at  one  end,  and  slightly  rounded 

*  Plate  VII.  fig.  4. 


154  BIVALVES. 

at  the  other ;  hinge  lateral,  with  a  single  tooth  in 
one  valve,  and  a  lateral  rib  locking  between  two 
teeth  in  the  other,  which  has  also  a  rib  ;  outside 
covered  with  an  olive  brown  skin  striated  trans- 
versely, each  stria  afterwards  taking  a  longitu- 
dinal direction ;  beneath  the  epidermis  the  shell 
is  grayish  white  with  purplish  streaks  ;  length 
about  one  inch,  breadth  from  one  open  end  to 
the  other,  seven  or  eight  inches. 

This  shell  is  common  on  most  of  our  sandy 
shores  ;  it  is  found  buried  a  foot  or  more  in  depth 
near  low  water. 


SOLEN  Radiatus* 


RADIATED  RAZOR  SHELL. 

aecific  character.  Shell  oval,  smooth,  thin, 
3,  striated  concentrically;  when  stripped  of 
its  green  epidermis,  it  appears  both  within  and 
without  of  a  delicate  violet  colour,  with  from  two 
to  four  white  longitudinal  rays,  which  become 
broader  towards  the  margin ;  hinge  with  two 
teeth  in  each  valve,  and  a  strong  white  depressed 
rib  extending  somewhat  obliquely  from  the  hinge 
towards  the  margin ;  shell  about  an  inch,  or  an 
inch  and  quarter  long,  and  from  three  to  four 
inches  broad. 

It  is  found  in  the  Indian  Ocean. 

*  Plate- VII.  figures 


TELLIN  A — TELLEN.         1 55 

GENUS.— TELLINA.* 

TELLEN. 

Generic  character.  Shell  bivalve,  equivalve, 
inequilateral;  shape  either  ovate  and  thickish, 
ovate  and  compressed,  or  suborbicular ;  the  area 
often  compressed,  having  a  flexuous  plait  or 
fold,  and  its  margin  curved  inwards,  so  that  it 
is  always  narrower  than  the  areola.  The  hinge 
has  either  one  or  two  central  teeth  in  each  valve, 
one  of  them  often  bifid  ;|  the  lateral  teeth  are 
remote,  and  sometimes  wanting  in  one  valve ; 
the  beaks  are  short,  and  usually  lean  towards 
the  ligament,  which  is  external. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

This  and  the  following  genus  are  so  very 
similar,  that  it  is  often  difficult  to  discriminate 
between  them.  If  however  a  shell  have  its 
anterior  slope  compressed,  or  any  indication 
of  its  margin  being  curved  inwards,  it  may  be 
known  immediately  as  a  Tellina.  The  Tellinae 
are  very  beautiful,  and  are  particularly  remark- 
able for  the  coloured  radiations  with  which  they 
are  adorned.  They  have  generally  a  fine  polish, 
and  are  sometimes  delicately  marked  with  minute 

*  Plate  VII.  figures  6.  7,  9,  9. 

f  Bifid,  cleft  in  two,  from  the  Latin  bis,  twice,  and  fid  f,  I  have 
cleft. 


156  BIVALVES. 

striae.  They  are  found  buried  in  the  sand  or 
fine  gravel  of  the  sea  shore  ;  a  few  of  them  in 
rivers  and  wet  ditches. 


TELLINA  Lingua  Fdu.* 

CATS5  TONGUE  TELLEN. 

Specific  character.  Shell  suboval,  thickish, 
somewhat  angular  at  the  anterior  end,  rough, 
covered  with  pointed,  rather  arched  erect  scales, 
disposed  in  a  quincunxf  order ;  colour  white,  often 
with  pale  pink  rays,  and  the  umbones  of  a  fine 
pink ;  length  about  an  inch  and  quarter,  breadth 
about  an  inch  and  three  quarters. 
It  inhabits  the  Indian  Ocean. 

TELLINA  Radiata. 
RADIATED  TELLEN. 

Specfiic  character.  Shell  ovate  oblong,  re- 
flected at  the  anterior  end,  striated  transversely, 
highly  polished ;  colour  sometimes  wholly  white, 
more  commonly  white  with  red  rays,  or  yellow 
transverse  bands  ;  the  hinge  is  not  central,  it  has 
two  small  teeth  in  one  valve,  and  one  in  the 
other,  and  the  lateral  teeth  are  remote ;  it  is 

*  Plate  VII.  figure  9. 

f  Quincunx,  disposed  alternately  as  in  rows  of  spots,  the  spots  of 
each  row  being  opposite  the  space  between  two  spots  of  the  next 
row  :  from  Latin  quinqwe,  five,  and  unx,  ounce,  because  the  weight 
representing  five  onnces  was  stamped  thus  *; 


CARDIUM — COCKLE.  157 

about  an  inch,  or  an  inch  and  half  long,  and 
more  than  twice  as  broad. 

The  Tellina  Radiata  is  found  very  abundantly 
in  the  West  Indies ;  it  also  inhabits  the  European 
ocean. 

TELLINA  Carnaria* 
ROSY  TELLEN. 

Specific  character.  Shell  suborbicular,  rather 
more  produced  on  one  side  than  the  other,  sub- 
pellucid,  marked  with  delicate  minute  crowded 
striae,  which  at  the  centre  are  oblique,  at  the 
shorter  end  curved  and  flexuous,  at  the  produced 
end  straight,  and  which  meeting  the  oblique 
striae  of  the  centre  form  with  them  angles  ;  the 
hinge  which  is  towards  the  posterior  side,  has 
two  small  teeth  in  one  valve,  and  one  in  the 
other,  with  strong  laminated  lateral  teeth ;  flesh 
colour  both  within  and  without,  length  about 
three  quarters  of  an  inch,  breadth  rather  more. 


GENUS.— CARDIUM.t 

COCKLE. 

Generic  character.     Shell  bivalve,  equivalve, 
equilateral,  convex ;  the  contour  of  many  of  the 

*  Carnaria  is  derived  from  the  Latin  earn  e,  with  flesh,  thw 
apeciea  being  so  called  from  their  flesh  colour 
f  Plate  VIII.  figures  1,2. 

14 


158  BIVALVES. 

species  when  viewed  with  either  of  the  slopes  in 
front,  exhibits  the  form  of  a  heart ;  indeed  all, 
more  or  less,  approximate  to  the  cordate  form  ; 
surface  either  ribbed,  striated,  or  furrowed  longi- 
tudinally ;  margins  toothed,  the  ribs  or  furrows  of 
the  two  valves  being  so  arranged  as  to  alternate 
at  the  margins,  and  to  fit  closely  into  each  other ; 
the  hinge  has  four  teeth  in  each  valve  ;  the  two 
central  are  oblique,  approximating,  and  articu- 
lating with  the  teeth  of  the  other  valve :  two 
lateral  teeth  remote,  inserted ;  the  beaks  are 
turned  inwards ;  the  umbones  are  turgid ;  the 
ligament  is  external. 


OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  Cardium  is  readily  distinguished  from 
the  shells  of  other  genera  by  the  peculiarity  of 
its  teeth  and  cordate  form ;  its  ribs  or  striee  also 
are  invariably  longitudinal.  The  mollusca  are 
furnished  with  two  short  unequal  tubes,  fringed 
with  hairs  at  their  extremities  ;  they  have  also  a 
muscular  foot  resembling  a  bent  arm,  with  which 
they  move  their  shell.  They  live  buried  under 
the  sand,  but  select  a  spot  near  the  shore,  as 
they  require  frequent  supplies  of  water,  and  to 
obtain  it,  are  continually  protruding  their  tubes. 
Many  of  the  species  afford  nutriment  to  the 
poorer  classes.  The  name  is  derived  from  the 
Greek  *a<p{a  (cardia)  -a  heart. 


CARDIUM COCKLE.  159 

CARDIUM  Eduk* 
COMMON  COCKLE 

Specific  character.  Shell  convex,  sometimes 
produced  at  the  posterior  end,  with  about  twenty- 
six  longitudinal  ribs  and  transverse  wrinkled 
striae,  which  in  old  specimens  appear  somewhat 
imbricated  ;  colour  whitish,  or  pale  ferruginous  ; 
about  an  inch  and  a  quarter  long,  and  an  inch 
and  a  half  broad. 

This  species  is  very  common  in  most  of  our 
inlets  and  bays  near  the  mouth  of  rivers,  where 
the  shore  is  sandy.  They  are  found  buried 
three  or  four  inches  under  the  surface.  The 
mollusca,  when  boiled,  afford  a  wholesome 
nourishment. 

CARDIUM  Tuberculatumj 
TUBERCULATED   COCKLE. 

Specific  character.  Shell  somewhat  orbicular, 
ponderous,  slightly  truncated  at  -  the  anterior 
side,  with  twenty-one  ribs,  the  anterior  ones 
having  sharp  tubercles,  and  the  posterior  thick 
transverse  scaly  plates ;  colour,  pale  brown,  with 
darker  transverse  bands  ;  breadth  not  quite  four 
inches,  and  rather  exceeding  the  length. 

This   shell,    and   the   Cardium    Echinatum, 

*  Edule.  eatable,  from  the  Latin  ed  ere,  to  eat 
f  Plate  VIII.  figure  2. 


160  BIVALVES. 

which  it  grea  ly  resembles,  are  found  in  abun- 
dance on  the  Paignton  sands  in  Torbay,  where 
at  low  tide  they  may  be  observed  with  their 
fringed  tubes  just  appearing  above  the  surface 
of  the  sea.  The  neighbouring  cottagers  collect 
them  in  baskets,  and  after  cleansing  them  in  cold 
spring  water,  fry  the  mollusc  a  in  a  batter  made 
of  crumbs  of  bread,  producing  a  wholesome  and 
savoury  dish ;  they  call  them  Red  Noses. 


GENUS.— MACTRA.* 

/ 

KNEADING-TROUGH. 

Generic  character.  Shell  bivalve,  equivalve,  in- 
equilateral, sometimes  gaping;  shape  frequently 
subtriangular,  hinge  with  the  cardinal  tooth  com- 
plicated,! and  an  adjacent  cavity  filled  by  the 
ligament  which  is  internal,  the  lateral  teeth 
laminar,  double  in  one  valve,  inserted. 


OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  shells  of  this  genus  are  clearly  marked 
by  their  angular  central  tooth,  and  internal  liga- 
ment. They  vary  little  in  form  or  colouring, 

*  Plate  VIII.  figures  3,  4. 

f  Complicated,  folded  together,  from  the  Latin  con,  with,  to- 
gether, and  plica  re,  to  fold." 


MACTRA PEPPER  MACTRA.  161 

and  do  not  display  much  beauty ;  they  are  usually 
semipellucid,  and  of  a  thin  delicate  appearance  ; 
the  surface  is  seldom  diversified  by  inequalities. 
The  prevailing  colour  is  blueish,  or  yellowish 
white,  sometimes  radiated.  The  animal  has 
not  the  power  of  progressive  motion,  but  by  the 
assistance  of  a  small  compressed  muscular  foot, 
is  enabled  to  change  his  position  a  little :  this 
organ  projects  at  one  end  of  the  shell,  and  at  the 
other  are  two  tubes  formed  by  the  mantle.  The 
name  Mactra  is  derived  from  the  Greek  /xa«rpa 
(mactra  a  kneading-trough. 

MAGTRA  Stultorum.* 

SIMPLETON'S  KNEADING-TROUGH. 

Specific  character.  Shell  subtriangular,  con- 
vex, thin, brittle,  semipellucid;  colour  white  gray, 
or  pale  brown,  radiate  more  or  less  from  the 
hinge  with  paler  stripes,  sometimes  of  a  purplish 
hue  about  the  beaks,  and  inside  of  the  valves ; 
the  umbones  are  gibbous ;  length  an  inch  and 
a  quarter,  the  breadth  one  and  three  quarters. 
Common  on  most  sandy  coasts. 

MACTRA  Compressa,  or  Piperata. 
PEPPER  MACTRA. 

Specific  character.  Shell  subtriangular,  roun- 
dish, compressed,  thin,  semipellucid,  finely  stri- 

t  Plate  VIII.  figure  4. 

14* 


162  BIVALVES. 

ated;  umbones  small,  central;  hinge  without 
lateral  teeth,  cartilage  cavity  large,  triangular, 
cardinal  teeth  small,  a  single  one  locking  into  a 
bifid  one  in  the  opposite  valve  ;  of  a  yellowish, 
reddish,  or  white  colour  often  stained  with  black 
occasioned  by  the  mud  in  which  it  resides  ;  about 
an  inch  and  quarter  long,  and  an  inch  and  half 
broad. 

This  is  one  of  the  most  beautiful  of  the  British 
species  of  Mactra;  it  is  chiefly  found  at  the 
mouth  of  inlets  or  rivers,  not  remote  from  fresh 
water  ;  for  though  it  always  seeks  a  spot  within 
reach  of  the  flux  of  the  tide,  it  delights  in  situa- 
tions over  which  fresh  water  occasionally  flows. 
It  lives  in  the  mud,  buried  about  five  or  six  inches 
deep.  The  animal  has  two  slender  tubes  of  a 
yellowish  colour  placed  near  together  at  the  an- 
terior end  :  one  about  three  inches  long  it  pro- 
trudes in  search  of  its  food,  which  consists  of  in- 
sects ;  these  may  be  seen  passing  up  its  trans- 
parent siphon,  drawn  in  with  the  current  of  water 
it  is  continually  receiving,  and  which  it  discharges 
at  the  shorter  tube,  retaining  only  the  nutritious 
matter  it  contained. 


GENUS.— DONAX.* 

WEDGE  SHELL. 


Generic  character.     Shell  bivalve,  equivalve, 
inequilateral ;    the  form  like  a  wedge,  broad, 


*  Plate  VIII.  figures  5,  6. 


DONAX — WEDGE  SHELL.       163 

thick,  and  obtuse  at  the  anterior  end,  and  gra- 
dually narrowing  and  lessening  at  the  posterior  ; 
the  margin  is  often  crenulate,  and  usually  gaping ; 
the  hinge  has  two  central  teeth  in  each  valve, 
and  one  remote  lateral  one ;  the  ligament  is  ex 
ternal. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  wedge-like  form  of  the  Donaces  easily 
distinguishes  them.  The  derivation  of  the  name 
from  toval  (donax)  an  arrow,  may  have  been 
adopted  either  as  indicative  of  the  sagittate  form, 
or  of  the  rapidity  with  which,  in  consequence  of 
its  peculiar  shape,  the  animal  can  dart  into  the 
sand,  whenever  danger  threatens.  One  species 
(Donax  Irus)  perforates  the  hardest  limestone, 
but  by  what  means  it  effects  such  a  lodgment  has 
not  been  ascertained ;  pieces  of  stone  are  often 
thrown  ashore  on  the  Devonshire  coast  filled 
with  these  shells  fitting  into  the  apertures  which 
they  have  pierced.  The  shells  of  this  genus, 
are  generally  of  a  fine  rich  purple  colour,  some- 
times marked  with  rays  of  purple  on  a  white 
ground.  Many  of  the  species  are  of  a  yellow 
olive  hue.  The  animal  has  two  long  slender 
tubes  not  joined  together,  and  a  lamellar  foot. 


164  BIVALVES. 

DONAX  Dentictdata.* 
TOOTHED  DONAX. 

Specific  character.  Shell  strong,  thick,  ovate, 
wedge-shaped,  with  longitudinal  striae,  the  inter- 
stices punctured;|  anterior  slope  rough,  with 
transverse  striae,  and  elevated  in  the  middle  in  a 
kind  of  keel ;  white  or  lead  colour,  usually  with 
a  few  purple  rays  proceeding  from  the  umbones, 
inside  purple  ;  very  concave  under  the  umbones ; 
margin  denticulated;  about  half  an  inch  long  and 
nearly  an  inch  broad. 

This  is  described  as  a  British1  species,  but  it 
is  rarely  found  on  our  coasts.  It  inhabits  the 
West  Indies,  Africa,  and  the  Mediterranean. 


GENUS.— VENUS.J 


VENUS. 

Generic  character.  Shell  bivalve,  equivalve, 
inequilateral,  closed  ;  shape  ovate,  suborbicular, 
or  subcordate  ;  both  the  area  and  areola  are  well 
defined,  the  area  is  generally  flattened,  and  the 

*  Plate  VIII.  figure  6. 

t  Punctured,  pricked  or  marked  with   small  dots,  from   tha 
Latin  punct  um>  a  point  or  dot. 
\  Plate  VIII.  figures  7,  8. 


VENUS — VENUS.  165 

areola  has  often  the  impression  of  a  heart ;  the 
hinge  has  three  approximate  cardinal  teeth,  the 
middle  one  is  longitudinal,  the  others  diverging ; 
there  is  a  lateral  tooth  in  a  few  species  ;  the 
beaks  are  turned  towards  the  areola ;  the  liga- 
ment is  external. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT 

The  shells  of  this  genus,  pre-eminent  for  the 
elegance  of  their  form,  and  the  beauty  of  their 
colouring,  have  in  consequence,  been  designated 
by  the  name  of  the  fabulous  goddess  of  beauty. 
The  three  approximate  teeth,  and  the  inclination 
of  the  beaks  towards  the  areola,  at  once  determine 
a  shell  to  be  a  Yenus,  but  these  marks  are  some- 
times wanting ;  in  a  few  species  there  are  four 
cardinal  teeth,  in  others  only  two  ;  this  variation 
in  the  hinge  has  led  to  a  subdivision  of  the 
genus. 

The  Venus  is  diffused  over  every  part  of  the 
world,  and  in  many  countries  affords  to  animals 
and  birds  a  nutritious  food.  It  is  curious  to 
observe  the  contrivances  by  which  the  sea-fowl 
endeavour  to  procure  the  mollusca  of  this  and 
other  genera;  they  have  been  seen  to  take 
advantage  of  a  moment,  when  the  valves  are 
open,  to  drop  a  pebble  between  them,  which 
being  thus  prevented  from  closing,  leave  the 
inmate  exposed.  When  they  find  the  shell  so 
hard  as  to  resist  all  their  efforts  to  break  it  with 
their  beaks,  they  ascend  to  some  lofty  eminence, 


166  BIVALVES. 

and  letting  it  drop  upon  rough  or  craggy  rocks, 
it  is  broken  in  the  fall,  and  the  animal  becomes 
their  prey.  The  mollusca  of  the  Yenus  have  two 
siphons  formed  by  the  mantle,  and  a  lamellar 
foot. 

VENUS  Mercenaria. 
MONEY  VENUS. 

Specific  character.  Shell  ponderous,  obliquely 
heart-shaped,  slightly  striated  transversely ;  pos- 
terior depression  cordiform ;  inner  margin  cre- 
nated ;  the  outside  is  greyish  or  brownish,  the 
inside  is  white,  with  a  violet-coloured  spot  at 
the  anterior  side ;  the  length  is  about  two  inches 
and  three  quarters,  the  breadth  about  three  inches 
and  a  half. 

The  Indians  of  North  America  cut  these 
shells  into  beads,  some  white  and  some  black  : 
of  these  they  form  their  wampum,  or  treaty-belts, 
which  are  symbolical  of  friendship.  They  also 
string  them  together  and  use  them  for  money. 
The  females  cover  the  shoes  they  wear  in 
dancing  with  these  shells,  which  in  their  move- 
ments being  struck  together  produce  a  sound 
resembling  the  tinkling  of  the  bells  used  by  the 
Israelitish  women,  and  mentioned  in  Isa.  iii.  16. 


SPONDYLUS THORNY  OYSTER.         167 

VENUS  Dysera* 
RIBBED  VENUS. 

Specific  character.  Shell  triangular,  convex, 
heart-shaped,  marked  with  distinct  concentric 
raised  ridges,  which  are  closely  cancellated  ;f 
the  longitudinal  striae  are  also  crossed  by  fine 
transverse  lines  ;  margin  crenated  ;  colour  gray, 
or  ivory  white,  variously  marked  with  chestnut 
brown  spots,  the  area  and  areola  are  of  the  same 
colour  as  the  spots  ;  diameter  about  an  inch. 

Found  on  the  shores  of  Germany,  America, 
and  the  East  Indies. 


GENUS.— SPONDYLUS. J  ' 

THORNY  OYSTER. 

Generic  character.  Shell  bivalve,  inequivalve, 
inequilateral,  fixed,  strong,  solid ;  surface  coarse 
and  rough,  with  either  lamellar  or  subulate 
spines,  or  ramifications ;  the  hinge  has  two 
strong  recurved  teeth  in  each  valve,  with  an 
intermediate  sinus  for  the  ligament;  the  lower 

*  Plate  VIII.  figure  8. 

f  Cancellated,  crossed  like  the  bars  of  a  window,  from  the  Latin 
cancelli,  lattice. 
I  Plate  VIII.  figures  9,  10. 


168  BIVALVES. 

valve  is  convex,  and  is  produced  at  the  apex 
into  a  projecting  beak  which  appears  as  if  it  had 
been  sliced  off  by  a  sharp  instrument,  presenting 
a  triangular  flattened  surface,  having  a  groove 
which  receives  the  decaying  part  of  the  ligament. 
The  shell  is  often  eared. 


OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

iThe  shells  of  this  genus  are  remarkable  not 
only  for  the  brilliancy  of  colouring,  which  most 
of  them  display,  and  for  the  singularity  of  their 
external  form,  but  also  for  the  clearness  and 
precision  of  the  characters  which  distinguish 
them  from  the  shells  of  other  genera.  The 
roughness  and  irregularity  of  their  appearance, 
their  two  strong  incurved  teeth,  and  the  inter- 
mediate sinus  for  the  ligament,  are  their  dis- 
criminative generic  marks.  The  genus  contains 
only  three  species,  one  of  which  has  not  the 
flattened  beak  and  external  ligament,  and  its 
shells  are  remarkable  for  being  plaited  longitu- 
dinally like  a  fan  half  opened ;  they  have  been 
separated  by  modern  conchologists  from  the 
Spondylus  under  the  significant  name  of  Plica- 
tula.*  The  Spondyli  adhere  to  rocks,  corals, 
and  other  marine  substances,  often  in  groups 
forming  large  masses.  The  animal  has  the 
edge  of  its  mantle  fringed  with  short  tentacular 
filament ;  it  has  a  small  radiated  foot.  From  a 

*  Plicatula,  a  little  fold,  from  plica,  a  fold.    Plate  VIII.  fig.  10 


CHAMA — CLAM  OR  CLAMP.  169 

supposed  external  resemblance  of  the  Spondylus 
to  the  oyster  it  has  been  called  the  Thorny 
Oyster;  its  scientific  name  is  derived  from  the 
Greek  <nrovSv\os  (spondulos)  the  head  of  an 
artichoke. 

SPONDYLUS  Gcedaropus* 
THORNY  OYSTER. 

Specific  character.  Shell  slightly  curved, 
spinous,  varies  greatly  in  colour,  size,  and  the 
form  of  the  spines ;  the  latter  are  generally 
laminated  or  tongue-shaped,  sometimes  foliated; 
the  colour  varies  from  saffron,  to  orange  and 
scarlet ;  the  size  is  about  two  inches  in  diameter. 
It  is  found  adhering  to  rocks  in  the  Mediter- 
ranean. 


GENUS.— CHAMA.f 


CLAM  OR  CLAMP. 

Generic  character.  Shell  bivalve,  solid,  exte- 
rior usually  coarse ;  hinge  has  a  gibbous  callo- 
sity inserted  obliquely  into  a  corresponding  sinus 
in  the  opposite  valve  ;  this  callosity  or  tooth  is 
either  simple  or  crenated ;  beaks  recurved ; 
form  various. 

*  Plate  VIII.  figure  9.       *       f  Plate  IX.  figures  1,  2,  3. 

15 


170  BIVALVES. 


OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

This  genus,  as  it  stands  in  the  Linnaean  clas- 
sification, contains  only  twenty-six  species,  but 
some  of  these  are  remarkably  dissimilar  in  their 
appearance.  It  includes  regular  and  irregular, 
equivalve  and  inequivalve  shells,  also  some  that 
are  attached  to  marine  substances,  and  others 
that  are  free.  The  callous  ridge  at  the  hinge  is 
the  most  decided  character  of  the  genus.  The 
name  is  derived  from  x*^  (cheme)  a  gaping, 
and  is  applicable  to  many  of  the  species  ;  it  is 
probable  that  all  those  which  have  an  opening  at 
the  margin,  possess  a  byssus,  by  which  they  are 
fastened  to  rugged  substances.  This  genus  af- 
fords subject  of  amazement  in  the  uncommon 
size  to  which  some  of  its  species  attain.  The 
Giant  Clam  (Chama  Gigas)  is  a  specimen  of 
unusual  magnitude  in  a  shell :  it  is  indeed  the 
largest  of  all  testaceous  productions.  One  of 
these  shells  described  by  Linnaeus,  weighed  four 
hundred  and  ninety-eight  pounds  ;  and  he  says 
that  its  inhabitant  furnished  one  hundred  and 
twenty  men  with  a  day's  food.  So  great  were 
the  weight  of  the  shell  and  the  strength  of  the 
muscles,  that  by  suddenly  closing  its  valves,  it 
cut  asunder  a  cable  ;  another  specimen  brought 
from  Sumatra,  is  preserved  at  Arno's  Vale,  in 
Ireland,  its  weight  is  five  hundred  and  seven 
pounds  ;  the  largest  valve  measured  four  feet 
six  inches  in  length,  and  two  feet  five  inches  and 


CHAMA HEART  CLAM.        171 

a  half  in  breadth.  A  specimen  of  this  extraor- 
dinary species,  forms  a  very  elegant  baptismal 
font  in  the  church  of  St.  Sulpice,  in  Paris  ;  it  was 
presented  by  the  Venetians  to  Francis  I.  Large 
pearls  are  occasionally  found  in  the  Chama ;  one 
exhibited  at  Sir  Joseph  Banks',  was  valued  at 
between  two  and  three  hundred  pounds.  The 
colour  of  the  Chama  Gigas,  is  a  dingy  white  : 
the  hinge  is  furnished  with  a  cartilage  of  a  dull 
colour,  which  when  cut  and  polished,  is  as  beau- 
tifully iridescent  as  Opal. 


CHAMA  Cor* 


HEART  CLAM. 

Specific  character.  Shell  equivalve,  globose, 
heart-shaped  when  viewed  from  the  posterior 
side  ;  thick,  strong,  smooth,  or  only  slightly 
striated  transversely  :  umbones  large  and  promi- 
nent, apices  involute,  and  turned  to  one  side  : 
colour  pale  yellowish  brown,  covered  with  a 
darker  epidermis,  decorticated  at  the  umbones. 
Shell  about  three  inches  long,  and  two  and  three 
quarters  broad. 

This  shell  has  but  very  rarely  been  found  in 
the  British  seas  ;  it  is  much  prized  on  account 
of  the  singular  and  graceful  beauty  of  its  form. 

*  Plate  IX.  figure  3. 


BIVALVES. 

CHAMA  Hippopus.* 


Specific  character.  Shell  equivalve,  inequi- 
lateral, thick,  heavy,  longitudinally  ribbed  and 
muricated  ;t  posterior  slope  heart-shaped, 
closed ;  margin  in  front  deeply  sinuous  ;  the 
colour  is  white  or  yellowish,  with  scattered  red- 
dish or  purplish  spots ;  commonly  about  two 
inches  long,  and  three  inches  and  a  quarter  in- 
side, but  it  sometimes  occurs  double  this  size. 

It  inhabits  the  East  Indian  ocean. 


GENUS.— ARCA4 

ARK. 

Generic  character.  Shell  bivalve,  equivalve, 
inequilateral ;  form  various,  often  oblong,  some- 
times orbicular;  hinge  with  numerous  small 
sharp  teeth  in  each  valve,  alternately  inserted 
between  each  other,  arranged  sometimes  in  a 
straight,  sometimes  in  a  curved  line. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  shells  of  this  genus  are  very  readily 
known,  by  their  numerous  small  teeth.  Some 

*  Plate  IX   figure  2. 

f  Muricated,  having  little  pointed  knots,  from  the  Latin  murex 
the  sharp  point  of  a  rock. 
{  Plate  IX.  figures  4,  o,.6. 


ARC A ARK.  173 

of  the  species  attach  themselves  to  rocks  by  a 
kind  of  byssus :  these  have  always  the  shell 
more  or  less  gaping  ;  but  the  greater  part  of  the 
Arks  live  buried  in  the  sand  at  a  short  distance 
from  the  shore  ;  all  are  marine.  The  mollusca 
have  no  external  siphons,  they  have  a  kind  of 
compressed  foot,  terminated  by  tendinous  fila- 
ments, which  are  affixed  to  rocks. 

ARCA  NO<B.* 

NOAH'S  ARK. 

Specific  character.  Shell  oblong,  roundish  at 
one  end,  elongated  at  the  other,  narrow,  and  in- 
clining to  angular ;  beaks  lateral,  remote  from 
each  other,  the  apices  incurved  with  a  broad 
smooth  space  between  them ;  teeth  in  a  straight 
line  ;  surface  strongly  striated  longitudinally,  and 
crossed  with  transverse  lines ;  margins  sinuous 
and  somewhat  gaping  ;  of  a  pale  rufous  colour, 
with  darker  oblique  bands  ;  the  broad  flat  space 
between  the  apices  has  a  few  distant  grooves 
radiating  from  the  umbones ;  length  about  an 
inch,  breadth  two. 

This  singular  shell  much  resembles  the  hulk 
of  a  ship  ;  the  flattened  area  and  areola  may  be 
considered  as  the  deck,  the  pointed  end  the 
prow,  the  gibbous  and  rounded  end  the  stern, 
and  the  acute  edge  of  the  united  margins  has  the 
appearance  of  the  keel.  The  form  of  the  shell 

*  Plate  IX.  figure  6. 

15* 


174  BIVALVES. 

suggested  the  name  of  Noah's  Ark,  and  from 
this  fancied  resemblance  in  one  species  to  the 
ark,  the  genus  owes  its  designation. 
{    Inhabits  the  Mediterranean,  Indian  Ocean, 
West  Indies,  and  Britain. 

ARCA  Undata. 
LETTERED  ARK. 

Specific  character.  Shell  suborbicular,  nearly 
smooth,  with  faint  reticulated")"  striae ;  margin 
crenated ;  teeth  in  a  curved  line  ;  colour  white, 
variegated  with  yellowish  red  spots,  in  undulated 
transverse  bands. 

Inhabits  the  West  Indies,  and  shores  of  Italy. 


GENUS.— OSTREA.J 

OYSTER,  SCALLOP,  OR  PECTEN. 

Generic  character.  Shell  bivalve,  generally 
inequivalve,  inequilateral,  more  or  less  eared; 
hinge  without  teeth,  but  furnished  with  an  ovate 
sinus,  in  which  is  fixed  an  elastic  cartilage ;  it 
has  generally  lateral  transverse  grooves. 

*  Plate  IX.  figure  5. 

f  Reticulated,  having  the  appearance  of  net  work,  from  the 
Latin  reticulum,  a  small  net. 
J  Plate  IX.  figures  7,  8. 


OSTREA — OYSTER,  SCALLOP.  175 


OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

This  genus  contains  shells  very  different  in 
their  general  appearance,  but  united  by  the  pe- 
culiarity in  the  hinge,  which  is  toothless,  and 
has  an  elastic  cartilage  inserted  into  a  sinus.  It 
may  be  divided  into  two  families,  the  Pecten  or 
Scallop,  and  the  Oyster,  which  are  separated  by 
very  marked  distinctions. 

The  Pecten  is  of  a  regular  orbicular  form,  and 
generally  eared ;  its  surface  is  adorned  with  di- 
vergent ribs,  which  proceed  from  the  apices  to 
the  circumference,  where  they  terminate  in  a 
scalloped  margin.  The  shells  of  this  division 
usually  display  brilliant  colours. 

The  second  division  contains  the  species  more 
or  less  resembling  the  common  oyster ;  these 
shells  are  irregular  in  their  form,  have  a  rugged 
and  laminated  exterior,  with  one  valve  more  con- 
cave than  the  other,  are  generally  without  ears, 
and  their  colour  is  gray  or  black. 

The  Pectens  are  described  as  possessing  asto- 
nishing powers  of  locomotion,  considering  the 
inferiority  of  their  organization ;  but  dexterity 
and  ingenuity  frequently  compensate  for  natural 
deficiency.  They  have  the  power  of  progressive 
motion,  both  on  land  and  in  the  water.  When 
the  animal  happens  to  be  left  on  the  shore  by 
the  retiring  tide,  it  opens  its  valves  to  their  full 
extent,  and  closing  them  with  great  muscular 
power,  is  thrown  forward  five  or  six  inches  by  a 


176  BIVALVES. 

sudden  leap.  In  this  manner  it  reaches  the  sea ; 
should  the  weather  be  calm,  it  raises  one  of  its 
valves,  which  catching  the  breeze,  acts  as  a  kind 
of  sail,  while  the  other  resting  on  the  surface, 
supports  the  floating  animal;  when  danger 
threatens,  the  shell  is  closed,  and  sinks  securely 
to  the  bottom  of  the  sea.  Many  of  the  Pectens 
possess  the  power  of  forming  threads,  by  which 
they  anchor  themselves  to  floating  timber,  and 
by  this  means  find  protection,  when  the  sea  is 
agitated  by  storms  and  tempests.  These  varied 
means  of  escaping  danger  are  no  doubt  afforded 
as  a  necessary  protection  against  their  numerous 
enemies.  The  pilgrims  who  in  former  days 
visited  Jerusalem,  to  pay  their  devotions  at  the 
holy  sepulchre,  on  their  return  wore  these  shells 
in  their  caps  as  trophies  of  their  achievement  in 
crossing  the  seas  for  this  sacred  purpose  ;  and 
in  commemoration  of  this  superstitious  act  of 
devotion,  it  was  often  granted  them  to  have 
,Pectens  engraved  in  their  coats  of  arms,  that  a 
record  of  their  religious  zeal  might  be  handed 
down  to  posterity. 

The  second  division  of  Ostrea,  contains  the 
shells  which  resemble  the  common  oyster  ;  they 
differ  from  the  Pectens  as  much  in  their  habits  as 
in  their  appearance.  They  are  reputed  to  be 
some  of  the  most  sluggish  of  animals,  and  to 
have  very  limited  powers  and  faculties  ;  but  whilst 
we  cannot  fail  to  observe  this  destitution,  we 
trace  the  goodness  of  the  Creator,  who  has 
placed  them  in  situations  not  exposed  to  danger, 
and  bestowed  upon  them  an  organization  that 


OSTREA— OYSTER,  SCALLOP.     177 

requires  but  little  to  satisfy  it.  The  only  nou- 
rishment they  need  is  brought  to  them  by  the 
ever-flowing  waves,  and  they  scarcely  exhibit 
any  symptom  of  life,  but  that  of  opening  their 
valves  to  receive  the  water,  and  then  closing  them 
for  security.  Firmly  attached  to  the  rocks,  and 
enclosed  within  their  strong  testaceous  dwelling, 
they  are  protected  against  surrounding  dangers. 
Some  of  the  species  effect  a  change  in  their  posi- 
tion by  a  curious  contrivance  ;  they  manage  to 
bolster  up  one  valve  in  the  sand  or  mud,  and 
having  thus  fixed  themselves  erect,  they  open 
their  shells,  and  the  flowing  or  reflux  of  the  tide 
forces  them  over  by  the  pressure  of  the  water 
The  animal  has  neither  siphon  nor  foot. 


OSTREA  Edulis. 

COMMON  OYSTER. 

Specific  character.  Shell  more  or  less  orbi- 
cular, inclining  to  oval,  but  subject  to  much  vari- 
ation in  form  and  size,  very  irregular,  imbricated 
with  scaly  laminae  ;  upper  valve  small  and  flat- 
tened, the  other  convex ;  inside  pearly  white, 
outside  dull  brown. 

Oysters  are  generally  found  with  their  lower 
valves  fixed  to  rocks  or  loose  stones,  and  fre- 
quently to  one  another.  Most  of  our  rocky 
coasts  abound  with  these  shells,  but  Essex  and 
Suffolk  chiefly  are  celebrated  for  them.  They 
are  dredged  up  by  a  kind  of  net,  with  an  iron 


178  BIVALVES. 

scraper  at  the  mouth,  and  are  immediately 
stowed  in  pits  formed  for  the  purpose  in  the  salt 
marshes,  which  are  overflowed  only  at  spring- 
tide, and  from  which  sluices  let  the  salt  water 
escape,  retaining  a  depth  of  about  eighteen  feet. 
The  water  being  stagnant,  in  warm  weather  it 
becomes  green,  and  in  a  few  days  the  oysters 
acquire  the  same  tinge  ;  they  are  then  held  in 
great  estimation  in  the  market,  but  they  do  not 
attain  their  greatest  perfection  under  six  or  eight 
weeks. 

Oysters  are  not  considered  fit  for  the  table  till 
they  are  about  a  year  and  half  old,  and  the  fish- 
ermen know  their  age  by  the  increase  in  the  size 
of  the  distance  which  separate  the  circles  of 
laminae  in  the  convex  valve.  When  young  shells 
happen  to  be  taken,  they  are  always  rejected  and 
cast  back  into  the  sea.  Great  Britain  has  for 
many  ages  been  noted  for  its  oysters,  which  in 
former  times  were  sent  as  a  peculiar  delicacy  to 
the  epicures  of  Rome. 


OSTREA  Malleus* 


HAMMER  OYSTER. 

Specific  character.  Shell  flexuous,  elongated 
at  the  base,  often  produced  into  two  lobes  giving 
it  somewhat  the  form  of  a  hammer,  from  whence 
it  derives  its  name;  outside  imbricated  with 

*  Plate  IX.  figure  8. 


OSTREA OYSTER,  SCALLOP.     179 

scaly  lamina ;  the  colour  generally  dark  gray  or 
blackish  ;  inside  very  glossy,  pearly,  and  tinged 
with  blue ;  it  is  about  five  or  six  inches  long, 
and  four  or  five  across  from  the  extremities  of 
the  two  lateral  robes. 

This  shell  is  much  prized  on  account  of  its 
very  singular  appearance.  It  is  found  in  the  In- 
dian Ocean :  its  animal  forms  a  byssus  which 
passes  through  a  small  opening  in  the  shell  near 
the  beaks. 


PEGTEN  MaximuB. 


GREAT  SCALLOP. 

Specific  character.  Shell  inequivalve,  with 
equal  auricles  ;  upper  valve  flattish,  depressed 
near  the  hinge,  lower  valve  convex  ;  the  surface 
has  about  fourteen  rounded  ribs,  is  longitudinally 
grooved,  and  very  finely  striated  transversely ; 
the  lower  valve  is  white,  tinged  with  red  ;  upper 
valve  reddish  brown  or  spotted  with  pink  and 
brown ;  inside  white  with  a  rufous  brown  margin ; 
length  five  inches,  breadth  six. 

This  shell  is  not  uncommon  on  some  of  our 
coasts,  particularly  at  the  mouth  of  large  rivers  ; 
it  is  frequently  sold  for  the  use  of  the  table,  and 
is  much  esteemed  as  a  nutritious  diet.  It  is 
asserted  by  fishermen,  that  they  are  taken  in  the 
greatest  quantities  after  a  fall  of  snow.  This 
was  the  species  worn  by  the  Pilgrims  to  the 
Holy  Land. 


180  BIVALVES. 

GENUS.— ANOMIA.* 

ANOMIA,  OR  ANTIQUE  LAMP. 

Generic  character.  Shell  bivalve,  inequivalve, 
sub  orbicular ;  one  valve  flattened,  and  often 
perforated  near  the  apex,  the  other  more  con- 
cave, and  sometimes  having  its  beak  produced 
and  curved  over  the  hinge  ;  hinge  toothless, 
having  a  linear  projection  which  is  united  under 
the  beak  to  the  opposite  valve  by  a  strong  liga- 
ment. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

This  genus  contains  a  variety  of  shells  mate 
rially  differing  in  their  appearance.  The  perfo- 
ration in  one  of  the  valves  for  the  emission  of  a 
ligament,  by  which  the  animal  adheres  to  marine 
substances,  is,  perhaps,  the  most  general,  but 
not  an  invariable,  characteristic. 

The  Anomiae  are  now  arranged  in  two  princi- 
pal groups,  very  clearly  distinguished  from  each 
other.  The  shells  of  one  division  retain  the 
name  of  Anomia,  and  very  much  resemble  a 
small  oyster  in  their  appearance  ;  like  them  they 
are  fixed  and  stationary,  living  and  perishing  on 
the  spot  where  the  egg  was  first  deposited. 
They  are  attached  by  means  of  a  bony  appen- 

*  Plate  IX.  figure  9;  plate  X.  figure  1. 


ANOMIA — ANTIQUE  LAMP.  181 

dage,  having  a  dilated  base  ;  this  is  in  fact  only  a 
prolongation  of  the  adductor  muscle  of  the  ani- 
mal ossified  at  its  outer  extremity.  When  the 
molluscum  contracts  the  muscle,  the  dilated 
portion  is  drawn  over  the  perforation  of  the  flat- 
tened valve  and  covers  it,  acting  as  an  opercu- 
lum.  So  firmly  are  the  shells  fixed  by  this  organ, 
that  they  cannot  be  removed  from  their  retreat 
without  destructive  violence,  the  ligament  and 
operculum  being  left  on  the  rock  to  which  they 
were  cemented.  The  form  of  the  Anomia,  like 
that  of  all  stationary  shells,  is  very  irregular,  be- 
ing usually  modified  by  the  substances  to  which 
it  adheres.  The  prevailing  colour,  of  this  genus 
is  a  dingy  yellow,  or  dusky  white  ;  the  shells  are 
generally  thin,  fragile,  delicate,  and  would  be  ill- 
fitted  to  contend  with  the  dangers  of  their  dwel- 
ling in  the  boisterous  ocean,  had  not  He  who 
placed  them  amid  its  perils,  exercised  his  com- 
pensatory providence,  and  anchored  them  se- 
curely in  its  depths. 

The  other  family  of  this  genus  now  bears  the 
name  of  Terebratula.  The  shells  which  it  con- 
tains are  distinguished  by  the  graceful  elegance 
of  their  form,  which  resembles  a  Grecian  lamp, 
and  from  hence  they  are  called  the  Antique 
Lamps.  The  concave  valve  of  the  Terebratula 
has  its  beak  produced,  curved  over  the  other 
valve  and  perforated  at  the  apex ;  the  smaller 
valve  is  furnished  with  two  slender  shelly  pro- 
cesses which  are  sometimes  short,  simple,  and 
recurved ;  sometimes  long,  branching  and  cros- 
sing each  other ;  their  use  is  not  ascertained,  but 
16 


182  BIVALVES 

it  is  supposed  that  they  are  supports  for  the 
animal.  The  Terebratulae  inhabit  the  depths  of 
the  ocean :  they  are  parasitical,  being  attached 
to  various  submarine  substances  by  a  tough 
short  stalk,  which  differs  from  the  ligament  of 
the  Anomia  in  being  formed  of  numerous  closely 
united  fibres,  separating  a  little  at  the  end,  by 
which  they  are  attached  to  the  stone.  The 
mollusca  inhabiting  these  shells  are  remarkable 
for  two  long  fringed  arms,  rolled  up  in  a  spiral 
form  within  the  shell  when  at  rest,  but  which 
they  protrude  when  hunger  prompts  them  to 
seek  for  their  food. 

ANOMIA  Ephippium* 
WRINKLED  ANOMIA. 

Specific  character.  Shell  suborbicular,  irre- 
gular, wrinkled,  sinuous  at  the  margin ;  inside 
pearly  and  iridescent ;  colour  yellow,  reddish, 
or  white ;  varies  from  two  to  three  inches  in 
diameter. 

This  shell  belongs  to  the  division  still  bearing 
the  name  of  Anomia.  It  adheres  to  other  bodies, 
and  particularly  oysters,  and  receives  the  im- 
pression of  the  substances  to  which  it  is  affixed, 
its  form  being  modelled  by  the  circumstances 
under  which  it  adds  to  its  size.  Some  specimens 
have  been  taken  from  the  Pecten  Maximus 
exhibiting  clearly  the  impression  of  its  ribs. 

*  Plate  X.  figure  1. 


MYTILUS — MUSCLE.  183 

ANOMIA  Psittacea* 
PARROT  BEAK  ANOMIA. 

Specific  character.  Shell  oval,  horny,  pel- 
lucid ;  the  beak  much  produced,  curved,  and 
perforated,  the  hole  subtriangular ;  margin  sinu- 
ated,  entire ;  surface  finely  striated  longitudinally; 
colour  is  blackish,  or  greenish  brown ;  length 
about  three-quarters  of  an  inch  exceeding  the 
breadth. 

This  shell  belongs  to  the  Terebratulae :  it 
inhabits  the  Indian  Sea  and  Greenland, 


GENUS.— MYTILUS.t 

MUSCLE. 

Generic  character.  Shell  bivalve,  rough,  gene- 
rally affixed  by  a  byssus  to  marine  substances ; 
hinge  mostly  without  teeth,  marked  by  a  furrow 
or  subulate  line  excavated  longitudinally — this 
line  is  crenated  in  some  of  the  species  ;  shape 
generally  a  long  oval,  sometimes  lobed,  some- 
times elongated  at  the  beaks. 

BSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

Though  all  the  Mytili  are  not  inseparably 
attached  to  other  substances,  all  are  by  some 

*  Plate  IX.  figure  9.  f  Plate  X.  figure  2. 


184  BIVALVES. 

means  rendered  stationary ;  the  silky  filaments 
produced  by  some  of  the  species  are  entwined 
in  the  coralines  and  stones  at  the  bottom  of  the 
sea,  and  securely  anchor  the  group  of  muscles 
found  there.  Others  of  the  species  perforate 
rocks  or  even  large  shells,  and  form  for  them- 
selves at  once  their  residence  and  grave.  The 
Mytili  which  have  their  beaks  nearly  terminal 
and  pointed,  and  are  of  a  dark  colour,  much 
resemble  a  mouse,  and  from  the  circumstance  of 
a  few  species  being  like  this  animal  the  genus 
has  received  their  name,  which  is  derived  from 
/zimAoj  (mutilos)  the  diminutive  of  ^  (a  mouse.) 
Some  of  the  species  have  their  base  elongated 
with  lobes  on  each  side,  and  bear  a  resemblance 
to  a  bird  in  full  flight.* 

MYTILUS  EdutisJ 
COMMON  MUSCLE. 

Specific  character.  Shell  oval,  pointed  at  the 
beaks  ;  sides  much  sloped,  flattish  on  the  anterior 
and  rather  angular  and  carinate  at  the  posterior 
end;  hinge  terminal;  beneath  the  margin  are 
several  tooth-like  crenulations  ;  colour  often  of  a 
rich  blue  when  deprived  of  its  epidermis  which  is 
brown ;  inside  blue  about  the  margin,  and  whitish 
in  the  middle,  length  from  two  to  three  inches, 
and  about  half  as  broad. 

*  Plate  X.  figure  3.  f  Plate  X.  figure  2 


MYTILUS COMMON  MUSCLE.  185 

This  shell  is  the  most  common  of  all  the  British 
species,  and  is  found  in  large  beds,  attached  by 
a  byssus.  The  mollusca  have  a  tongue-shaped 
muscular  foot,  capable  of  great  powers  of  elon- 
gation and  contraction  ;  with  this  instrument 
they  are  able  to  effect  a  progressive  motion. 
Forming  a  furrow  in  the  sand,  and  placing  their 
shell  erect,  they  stretch  out  the  foot,  which  be- 
ing rather  viscid,  adheres  to  the  ground,  and  an 
effort  being  made  to  contract  it,  the  shell  is  drawn 
along  the  groove.  Thus  alternately  extending 
and  contracting  this  muscular  instrument,  the 
Mytilus  contrives  to  creep  to  a  convenient  situa- 
tion for  anchorage,  and  by  means  of  this  same 
foot  it  then  forms  a  coarse  byssus,  which  fixes  it 
to  the  chosen  spot.  Often  towards  the  end  of 
autumn,  a  little  crab  is  found  sheltering  itself 
within  the  valves  of  the  muscle.  This  little 
creature  is  called  the  Pisum,  or  Pea  Crab  :  it  is 
supposed  to  have  been  placed  in  the  shell  of  the 
Mytilus  and  other  Bivalves,  to  assist  by  its  saga- 
city, the  more  limited  powers  of  its  host,  and  to 
repay  him  for  a  safe  retreat,  by  going  in  search 
of  provender,  and  sharing  it  with  him. 

MYTILUS  Margaritiferus.* 
PEARL-BEARING  MUSCLE. 

Specific  character.  Shell  sub  orbicular,  com- 
pressed, the  margin  rounded,  except  on  the  hinge 

*  Plate  X.  figure  3. 

16* 


186  BIVALVES. 

side  where  it  is  straight  and  transverse  ;  surface 
imbricated  with  transverse  membranaceous 
scales,  having  the  laminae  toothed  in  rays  ;  colour 
commonly  greenish  or  pale  chestnut,  inside 
pearly  and  iridescent ;  the  full  grown  shells  are 
sometimes  ten  or  twelve  inches  long  and  rather 
less  in  breadth  :  they  are  thick  and  ponde- 
rous, but  young  specimens  are  thin,  brittle,  and 
slightly  eared. 

This  species  is  much  celebrated  for  producing 
pearls,  a  calcareous  substance  similar  to  that  of 
the  shell  itself,  and  arranged  in  concentric  layers. 
Acids  have  the  same  effect  upon  pearls  as  upon 
other  carbonates  of  lime,  and  Cleopatra  is  said  to 
have  dissolved  in  vinegar  one  of  great  value  in 
order  to  display  her  magnificence  by  this  costly 
draught.  The  pearl  fishery  is  a  very  dangerous 
employment ;  it  is  principally  carried  on  in  the 
Persian  Gulf  and  the  neighbourhood  of  Cey- 
lon ;  the  season  for  the  fishery  lasts  about  a  fort- 
night. Numerous  boats  are  despatched  to  the 
station  where  it  is  carried  on,  each  containing 
twenty  men,  ten  of  whom  are  employed  in  row- 
ing and  assisting  the  divers.  They  descend 
alternately  in  parties  of  five,  and  thus  time  is  af- 
forded for  all  to  recover  themselves  after  their 
violent  exertion.  The  diver  has  a  rope  attached 
under  his  arms,  the  end  of  which  is  given  to  the 
men  in  the  boat ;  round  his  neck  is  slung  a  net, 
distended  at  the  opening  by  a  hoop.  Closing 
his  nostrils,  he  commits  himself  to  the  sea,  with 
a  perforated  stone  often  or  twenty  pounds  weight 
affixed  to  his  foot,  to  accelerate  his  descent.  He 


PINNA SEA  WING.  187 

sinks  generally  a  depth  of  twenty  or  thirty  yards  ; 
then  quickly  proceeding  to  his  work,  he  tears  the 
muscles  from  their  bed,  fills  his  net,  makes  a 
signal  and  is  drawn  up  again  to  the  surface. 
Many  and  great  are  the  dangers  attendant  on 
this  employment.  The  greedy  shark  marks  the 
diver  for  his  prey,  who  seeks  to  elude  his  obser- 
vation by  muddying  the  water.  A  large  flat  fish 
also  sometimes  attacks  him,  and  keeps  him  un- 
der water  till  he  is  drowned.  When  drawn  up  in 
safety  to  his  vessels,  he  often  in  consequence  of 
his  exertion  discharges  blood  from  his  mouth  and 
nostrils.  The  divers  rest  and  labour  alternately, 
during  periods  of  about  ten  minutes. 


GENUS.— PINNA* 

SEA  WING. 


Generic  character.  Shell  bivalve,  equivalve, 
fragile,  thin,  gaping  at  one  end,  and  furnished 
with  a  byssus  ;  shape  subtriangular,  narrow  at 
the  beaks,  and  expanding  to  a  considerable 
breadth  at  the  opposite  extremity ;  hinge  with- 
out teeth ;  valves  united  by  a  long  external 
ligament. 


*  Plate  X.  figure  3. 


188  BIVALVES. 


OBSERVATIONS  ON  THE   SHELL  AND  ITS 
INHABITANT. 

The  Pinna  seems  to  form  the  connecting  link 
between  the  univalves  and  bivalves,  for  though 
composed  of  two  valves,  it  is  incapable  of  mo- 
ving on  its  hinge.  It  is  generally  found  at  a  small 
distance  from  the  shore,  fixed  in  the  mud  at  its 
smaller  end,  and  standing  erect.  The  animal 
forms  a  byssus,  the  fibres  of  which  are  aggluti- 
nated, either  to  the  sand,  gravel,  roots  of  marine 
plants,  broken  shells,  or  any  matter  within  its 
reach.  The  byssus  of  the  Pinna  is  much  more 
fine  and  delicate  than  that  of  the  muscle ;  the 
filaments  are  long,  silky,  and  of  a  bright  lustre  ; 
the  natural  colour  is  of  a  rich  golden  brown,  but 
it  readily  receives  any  tint.  The  animal  possesses 
a  kind  of  tubular  instrument,  furnished  with  a 
gland  which  secretes  a  glutinous  substance  :  by 
means  of  a  slight  pressure,  a  drop  of  this  liquid 
is  deposited  on  the  spot,  to  which  the  byssus  is 
to  be  attached :  by  the  retraction  of  the  foot,  a 
silken  filament  is  drawn  out,  and  this  operation 
being  repeated  some  thousands  of  times,  a  beau- 
tiful tuft  of  silky  fibres  is  produced.  The  Pinnae 
are  much  sought  after  on  the  coasts  of  Sardinia 
and  Corsica  for  the  sake  of  the  byssus ;  they 
are  fished  up  with  an  instrument  which  consists 
of  two  semicircular  bars  of  iron  fastened  together 
at  each  end,  but  three  inches  distant  from  each 
other  at  the  centre.  At  one  end  is  a  hollow 
handle,  in  which  a  pole  is  fixed,  at  the  other  is  a 


PINNA SEA  WING.  189 

ring,  to  which  a  cord  is  fastened.  When  a  Pinna 
is  discovered,  the  iron  is  let  down  slowly  over 
the  shell,  which  is  then  twisted  round  and  drawn 
out.  When  a  sufficient  number  have  been 
caught,  the  silk  is  cut  off,  and  after  being  twice 
soaked  in  tepid  water,  and  once  in  soap  and 
water,  is  spread  out  to  dry  in  some  cool  and 
shady  place.  Whilst  it  is  yet  moist,  it  is  again 
softly  rubbed  and  separated  with  the  hand,  and 
then  spread  out  again.  When  thoroughly  freed 
from  moisture,  it  is  drawn  through  a  comb  with 
the  teeth  wide  apart,  and  afterwards  through  a 
similar  instrument,  with  finer  and  closer  teeth. 
The  more  common  silk  is  thus  prepared,  but 
that  which  is  destined  for  finer  works,  is  after- 
wards drawn  through  closer  iron  combs  or  cards. 
It  is  spun,  two  or  three  of  the  threads  being 
mixed  with  one  of  real  silk,  and  then  knitted  into 
gloves,  stockings,  and  even  whole  garments. 
When  the  piece  is  knitted,  it  is  washed  in  clean 
water  mixed  with  lemon  juice,  gently  beaten  be- 
tween the  hands,  and  smoothed  with  a  warm 
iron.  The  shells  of  the  Pinna  are  often  orna- 
mented with  elevated  longitudinal  ribs,  crossed 
by  striae,  sometimes  terminated  by  imbricated 
arched  scales,  or  prominent  tubular  spines.  Some 
of  the  young  shells  of  this  genus  are  less  than  an 
inch  in  length,  whilst  the  adults  often  exceed 
three  feet.  The  Pinna  as  well  as  the  Muscle, 
was  much  celebrated  by  the  ancients  ;  they  sup- 
posed it  to  harbour  within  its  shell  a  small  crus- 
taceous  animal,  a  kind  of  shrimp,  which  was  said 
to  be  of  the  greatest  use  to  its  companion,  by 


190  BIVALVES. 

warning  it  of  the  vicinity  of  the  prey  upon  which 
it  subsists,  or  of  the  approach  of  its  great  enemy 
the  Sepia.  Many  stories  are  related  of  the  ami- 
able habits  of  this  pair,  and  of  the  mutual  ser- 
vices they  render  each  other.  The  truth  of 
these  accounts  are  much  confirmed  by  small  ani- 
mals of  the  crustaceous  tribe  being  continually 
found  in  the  shells  of  the  Pinna  and  Muscle. 
The  ancients  have  celebrated  these  histories,  by 
making  them  the  subject  of  poetry  ;  the  follow- 
ing verses  are  translated  from  a  Latin  author, 
and  are  very  descriptive  of  the  habits  of  the 
Pinnae. 

In  clouded  deeps  below  the  Pinna  hides, 
And  through  the  silent  path  obscurely  glides  ; 
A  stupid  wretch,  and  void  of  thoughtful  care, 
He  forms  no  bait,  nor  lays  the  tempting  snare , 
But  the  dull  sluggard  boasts  a  crab  his  friend, 
Whose  busy  eyes  the  coming  prey  attend. 
One  room  contains  them,  and  the  partners  dwell 
Beneath  the  convex  of  one  sloping  shell ; 
Deep  in  the  watery  vast  the  comrades  rove, 
And  mutual  interest  binds  their  constant  love. 
That  wiser  friend  the  lucky  juncture  tells, 
When  in  the  circuit  of  the  gaping  shells 
Fish,  wandering,  enter;  then  the  bearded  guide, 
Warns  the  dull  mate,  and  pricks  his  tender  side  j 
He  knows  the  hint,  nor  at  the  treatment  grieves, 
But  hugs  the  advantage,  and  the  pain  forgives : 
His  closing  shells  the  Pinna  sudden  joins, 
And  'twixt  the  pressing  sides  his  prey  confines. 
Thus  fed  by  mutual  aid  the  friendly  pair 
Divide  their  gains,  and  all  their  plunder  share. 


The  name  Pinna,  which  is  sometimes  spelled 
with  one  n,  is  supposed  to  be  derived  from  twos 
(pinos)  the  dirt  or  mud ;  but  the  name  given  it 
by  British  conchologists  would  lead  us  to  take  its 
derivation  from  the  Latin,  pinna,  a  large  feather. 


QUESTIONS  ON  BIVALVES.  191 

PINNA  Pectinate* 
SPINY  SEA  WING. 

Specific  character.  Shell  triangular,  oblong, 
with  about  eleven  longitudinal  ribs,  having  con- 
cave spines,  which  increase  in  size  as  they 
approach  the  broadest  end ;  the  other  side  des- 
titute of  ribs,  but  obliquely  striated  up  to  the 
ribs  ;  shell  thin,  pellucid,  brittle,  of  a  light  brown 
colour,  darker  towards  the  beaks;  inside  of  a 
pearly  hue ;  breadth  three  inches  at  the  gaping 
end,  which  is  slightly  rounded ;  length  six  inches 
and  a  half. 

This  shell  inhabits  India ;  it  has  also  been 
found  on  the  coasts  of  Dorset  and  Sussex. 


QUESTIONS  ON  THE  BIVALVE 
SHELLS. 

1 .  Describe  the  part  of  a  Bivalve  shell  which 
unites  the  two  valves. 

2.  By  what  means  are  the  animals  able  to 
open  these  valves  1 

3.  What  is  the  meaning  of  the  terms  equi- 

*  Plate  X.  figure  4. 


QUESTIONS  ON  BIVALVES. 

valve,  inequivalve,  equilateral,  inequilateral,  and 
whence  are  these  terms  derived  ? 

4.  What  kind  of  animal  inhabits  bivalve  shells  ? 

5.  How  is  the  generic  character  of  bivalve 
shells  determined  ? 

6.  Name  the  parts   of  a  bivalve  shell,  and 
describe  the  situation  of  each  part. 

7.  What  is  the  generic  character  of  the  JVIya, 
and  what  are  its  distinguishing  marks  ? 

8.  Describe  the  manner  in  which  the  shell  of 
the  Mya  Margaratifera  is  peculiarly  suited  to 
the  situations  it  occupies. 

9.  What  are  pearls,  and  in  what  kind  of  shells 
are  they  found  ? 

10.  What   is  the  generic   character  of  the 
Solen,  and  how  is  it  distinguished  ? 

11.  Describe  the  habits  of  the  Solen. 

12.  What  is  the  generic  character  of  the  Tel- 
lina,  and  its  distinguishing  mark  1 

13.  What    is    the  generic  character  of  the 
Cardium,  and  which  are  its  distinguishing  marks  ? 

14.  Which  species   of  the  Cardium    afford 
food  to  the  poorer  classes  ? 

15.  What  is  the  general  appearance  of  the 
Mactrse? 

16.  What   is  the  generic  character  of  the 
Donax  1 

17.  What  is  the  generic  character  of  the 
Venus,  and  its  distinguishing  mark. 

18.  To  what  use  is  the  Venus  Mercenaria 
converted? 

19.  What  is  the  generic  character  of  the 
Spondylus  ? 


QUESTIONS  ON  BIVALVES.  193 

20.  What  is  the  generic  character  of  the 
Chama,  and  its  distinguishing  mark  ? 

21.  Give  an  account  of  the  Chama  Gigas. 

22.  What  is  the  generic  character  of  the  Area, 
and  its  distinguishing  mark  ? 

23.  What  difference  occurs  in  the  arrange- 
ment of  the  teeth  of  the  Area  1 

24.  What  is  the  generic   character   of  the 
Ostrea,  and  its  distinguishing  mark  1 

25.  Describe  the  two  great  families  into  which 
the  Ostrea  is  divided. 

26.  Describe  the  difference  in  the  habits  of 
the  Pecten  and  the  Oyster. 

27.  Describe  the  manner  of  taking  and  fat- 
tening the  common  oyster. 

28.  What  is  the  generic  character   of  the 
Anomia  1 

29.  Describe  the  two  families  into  which  the 
Anomia  is  divided. 

30.  What  is   the  generic   character  of  the 
Mytilus  ? 

31.  Describe   the   habits    of   the    common 
muscle. 

32.  Describe  the  pearl  fishery. 

33.  What  is  the   generic  character  of   the 
Pinna? 

34.  Why  is  the  Pinna  considered  as  a  link 
between  the  univalves  and  bivalves'? 

35.  Describe  the  habits  of  the  animal  inha- 
biting the  Pinna. 


17 


194  MULTIVALES. 


MULTIVALVES. 

This  class  according  to  Linnaeus,  contains 
three  genera.  The  generic  character  is  chiefly 
determined  by  the  number  of  valves  and  their 
position. 

GENUS.— PHOLAS* 

STONE  PIERCER. 

Generic  character.  Shell  with  two  primary 
valves  gaping  at  both  ends,  and  several  smaller 
accessory  valves  situated  upon  the  hinge  and 
posterior  slope  ;  hinge  recurved,  each  valve  has 
a  long  tooth  curved  inwards. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  shells  of  this  genus  are  thin,  fragile,  and 
usually  either  of  a  pure  or  dusky  white,  adorned 
with  beautiful  minute  fret  work  :  the  reticulations 
in  some  species  are  so  delicate  and  fine  as  to 
resemble  lace  ;  in  others,  they  are  coarser,  and 
approaching  to  small  basket  work.  The  Pho- 
lades  were  ranked  by  Linnaeus  among  the  mul- 
tivalves,  but  by  modern  conchologists  they  are 
generally  placed  with  the  bivalves.  The  two 

*  Plate  X.  figure  S. 


PHOLAS STONE  PIERCER.  195 

principal  valves  connected  by  a  hinge,  associate 
them  closely  to  the  latter,  while  the  small  testa- 
ceous plates  around  the  hinge  may  be  considered 
as  mere  appendages,  for  they  do  not  act  the  part 
of  valves.  The  Pholas  appears  the  connecting 
link  between  the  classes  of  bivalves  and  multi- 
valves.  So  gradual  are  the  steps  by  which  the 
scale  of  nature  proceeds,  that  it  is  of\en  difficult 
to  ascertain  precisely  the  line  which  separates  its 
great  divisions. 

The  Pholades  are  all  borers,  perforating  wood, 
clay,  limestone,  and  sometimes  burying  them- 
selves in  the  sand,  forming  a  retreat  in  which  they 
pass  their  lives.  The  name  marks  their  peculiar 
propensity,  being  derived  from  ^wAws  (pholeos)  a 
hiding  place.  The  largest  species,  and  the  finest 
specimens  are  most  frequently  found  in  chalk, 
which  being  the  softest  of  calcareous  substances, 
admits  of  a  more  easy  and  rapid  progress  to  the 
animal  than  the  indurated  stones  in  which  they 
are  sometimes  discovered.  How  they  effect 
their  lodgement,  is  still  a  subject  of  doubt  and 
inquiry.  Many  have  supposed  that  a  continued 
rotatory*  motion  would  in  time  produce  such  a 
cavity  as  they  inhabit,  but  as  it  is  exactly  fitted 
to  their  size,  it  cannot  be  easily  imagined  that 
the  animal  could  perform  this  motion  within  it. 
Another  circumstance  opposed  to  this  opinion 
is,  that  the  mollusca  whose  shells  are  perfectly 
smooth,  are  capable  of  producing  the  same  exca- 
vation as  those  which  have  a  surface  as  rough 

*  Rotatory,  like  a  wheel,  from  the  Latin  rota,  a  wheel. 


196  MULTIVALVES. 

as  a  file.  Many  have  supposed  that  the  animal 
must  possess  some  liquid  which  acts  as  a  solvent 
upon  the  substance  it  enters.  This  appears  the 
more  probable,  as  it  is  known  to  emit  a  phos- 
phorescent light ;  but  as  the  Pholades  pierce 
substances  of  so  very  different  natures,  it  appears 
that  the  same  substance  could  not  act  as  a  sol- 
vent to  them  all. 

The  difficulty  in  accounting  for  the  manner  in 
which  this  little  animal  forms  its  retreat,  should 
teach  us  how  easily  human  reason  is  baffled,  and 
lead  us  to  reflect  upon  the  condescending  wisdom 
displayed  for  the  accommodation  of  a  slug.  The 
entrance  is  the  smallest  part  of  the  dwelling  of 
the  Pholades,  and  hence  it  is  evident  that  they 
must  have  penetrated  the  rock  when  young  and 
small,  and  enlarged  their  perforations  as  they 
themselves  increased  in  dimensions.  The  posi- 
tion of  the  hole  is  always  oblique  to  the  horizon : 
its  form,  that  of  a  truncated  cone,  terminated  by 
a  rounded  cavity.  This  cavity  receives  the  body, 
while  the  farthest  end  is  occupied  by  the  probos- 
cis, which  is  continually  protruded  to  the  orifice 
to  procure  the  sea  water,  upon  which  it  subsists. 
The  proboscis  is  long,  pliable,  and  fleshy,  termi- 
nated by  a  corneous  substance,  which  is  den- 
tated  like  a  saw  at  its  extremity.  There  is  an 
opening  between  the  valves,  through  which  it  is 
projected,  and  a  case  into  which  it  fits.  At  the 
approach  of  danger,  the  mollusca,  by  means  of 
this  instrument,  eject  water  to  a  considerable 
height,  and  its  dentated  margin  leads  us  to  sup- 
pose, that  they  employ  it  in  the  work  of  perforation. 


PHOLAS — STONE  PIERCER.  197 

PHOLAS  Candida* 
WHITE  STONE  PIERCER. 

Specific  character.  Shell  oval,  obtuse,  nearly 
closed  at  the  anterior  end,  thin,  fragile,  almost 
transparent,  striated  transversely,  and  crossed 
by  finer  stria?  in  a  radiated  form  from  the  um- 
bones,  a  few  of  the  radii  at  the  larger  end  set  with 
short  spines  ;  hinge  smooth  and  reflected,  teeth 
slender  and  curved ;  one  valve  has  a  curved 
lamina  above  the  tooth ;  there  is  a  single  acces- 
sory valve  ;  the  colour  is  yellowish  white  ;  it  is 
about  three-quarters  of  an  inch  long,  and  three 
inches  broad. 

These  Pholades  inhabit  marine  rocks ;  they 
are  found  in  great  numbers  on  the  Devonshire 
coast ;  the  stone  in  which  they  are  imbedded  is  a 
cementation  of  the  finest  sand  and  limestone ; 
it  is  very  soft  when  first  taken  from  the  bed,  and 
so  absorbent  as  to  afford  sufficient  moisture  for 
the  purposes  of  life,  and  for  the  peculiar  actions 
o«f  the  mollusca.  The  animal  secretes  a  mild 
phosphorescent  solution,  which  would  be  of  suf- 
ficient power  to  decompose  the  rock  by  the  slow 
contact  of  its  gradually  increasing  bulk. 

*  Plate  X.  figure  8, 


17* 


198  MULTIVALVES. 

GENUS.— CHITON* 

COAT  OF  MAIL. 

Generic  character.  Shell  multivalve,  com- 
posed of  eight  valves,  rarely  of  seven  or  six ; 
form  convex,  oval ;  the  valves  are  arranged  in  an 
imbricated  manner,  the  margin  of  one  being 
incumbent  on  that  of  the  next ;  they  are  sur- 
rounded and  connected  by  an  elastic  coriaceous 
membrane,  which  is  either  scaly,  hairy,  or 
spinous,  and  allows  of  the  free  movement  of  the 
valves. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

The  Chitons  are  readily  distinguished  from  all 
other  testaceous  mollusca  by  the  form  of  their 
shell,  which  very  much  resembles  a  small  vessel 
or  boat  turned  upside  down,  and  by  the  peculiar 
arrangement  of  its  moveable  valves  attached  by 
a  coriaceous  membrane.  This  latter  substance 
is  capable  of  sufficient  distension  and  contrac- 
tion to  admit  of  considerable  play  in  the  valves, 
so  that  the  animal  can  roll  up  its  shell  into  the 
form  of  a  ball,  having  all  the  appearance  of  a 
wood-louse.  Contracted  and  covered  by  its 
scales  it  lies  like  a  pebble  at  the  bottom  of  the 

*  Plate  X.  figure  5. 


CHITON COAT  OF  MAIL.  199 

sea,  and  thus  contrives  frequently  to  escape  the 
vigilance  of  its  enemies.  The  mollusca  of  the 
Chitons  are  of  the  same  form  as  their  shells,  the 
plates  of  which  are  fixed  in  the  mantle ;  the  gills 
surround  their  bodies ;  they  breathe  only  water, 
and  have  a  fleshy  foot,  upon  which  they  creep. 
Their  abode  is  in  the  sea  at  an  inconsiderable 
depth  near  the  shore.  They  fix  themselves  for 
a  time  to  rocks  and  stones,  but  they  can  remove 
at  pleasure.  The  situation  and  formation  of  the 
valves  resemble  the  plates  which  constitute  a 
suit  of  armour,  or  coat  of  mail;  and  to  this 
resemblance  the  shell  owes  its  name,  which  is 
derived  from  x<™v  (chiton)  a  coat  of  mail. 

CHITON  Fasdcndaris. 
TUFTED  CHITON. 

Specific  character.  Shell  with  eight  valves, 
apparently  smooth,  but  when  viewed  through  a 
glass,  found  to  be  rough  like  shagreen,  except 
on  the  elevated  dorsal  ridge  ;  the  margin  is 
surrounded  with  tufts  of  whitish  hairs  at  the 
junction  of  each  valve,  there  are  also  two  tufts  in 
front,  making  altogether  eighteen.  The  colour 
is  brown  or  dark  gray,  often  mottled  ;  the  length 
is  rather  less  than  an  inch. 

The  animal  of  this  Chiton  adheres  to  oysters 
and  other  shells,  and  with  them  inhabits  the 
deep ;  it  is  also  found  on  stones.  It  is  not 
uncommon  on  the  coast  of  Devonshire ;  on  those 
of  Barbary  it  occurs  of  a  much  larger  size. 


200  MULTIVALVES. 

CHITON  Squamosus.* 
SCALY  CHITON. 

Specific  character.  Shell  with  eight  vaKcs, 
one  half  of  each  valve  is  striated  longitudinally, 
and  the  other  half  transversely;  the  margin 
scaly ;  the  outside  is  dark  brown,  more  or  less 
variegated  with  olive,  and  the  inside  is  light 
bluish  green ;  the  margin  is  beautifully  chequered 
with  light  green  and  dark  olive  scales. 

Inhabits  the  coasts  of  America. 


GENUS.— LEPAS.t 

BARNACLE. 

Generic  character.  Shell  multivalve,  more  or 
less  of  a  conical  form,  affixed  at  the  base ;  valves 
erect,  oval,  unequal,  varying  in  number,  most 
frequently  six. 

OBSERVATIONS  ON  THE  SHELL  AND  ITS 
INHABITANT. 

This  genus  consists  of  two  principal  divisions; 
the  shells  contained  in  the  one  are  sessile,  or 
affixed  at  their  base,  those  of  the  other  are 
peduncled. 

*  Plate  X.  figure  5.  f  Plate  X.  figures  6,  7. 


LEPAS BARNACLE.  201 

Though  dissimilar  in  their  appearance,  these 
shells  are  united  by  many  points  of  resemblance; 
they  are  all  more  or  less  of  a  conical  form,  com- 
posed of  several  valves,  and  are  parasitical.  The 
animals  inhabiting  them  are  very  similar,  and 
differ  much  from  other '  mollusca.  They  have 
no  head  or  eyes,  the  mouth  has  jaws,  with  horny 
laminae  or  erect  teeth;  but  the  most  singular 
part  of  their  structure  consists  in  the  numerous 
tentacular,  curled,  articulated  arms ;  these  vary 
in  number,  some  of  the  species  have  as  many  as 
twenty-four.  They  are  arranged  in  pairs,  and 
are  all  inserted  together ;  the  twelve  longest  are 
erect  and  arched,  appearing  like  curled  feathers  ; 
they  are  clear  and  horny;  each  joint  is  furnished 
with  two  rows  of  hairs  on  the  concave  side. 
The  animals  make  use  of  these  organs  to  catch 
their  prey,  and  are  continually  extending  and 
contracting  them.  The  twelve  smallest  are 
placed  in  front,  they  are  more  flexible,  and  more 
thickly  set  with  hairs  than  the  others. 

The  sessile  shells*  are  now  formed  into  a 
distinct  genus  called  Balanus  ;  they  adhere  im- 
mediately to  marine  substances  at  their  base,  and 
remain  immoveably  fixed  for  life  ;  the  form  of 
the  shell  is  conical,  and  the  valves  of  which  it  is 
composed  are  so  strongly  cemented  as  almost  to 
appear  like  a  single  piece.  From  the  construc- 
tion of  the  shell,  its  immoveable  walls,  and  its 
large  opening  at  the  apex,  the  animal  would 
be  in  a  very  exposed  and  perilous  situation, 

*  Plate  X.  figure  6. 


MULTIVALVES. 

had  not  the  compensatory  providence  of  the  Cre- 
ator been  exerted  in  affording  it  a  safeguard. 
This  consists  of  a  very  efficient  operculum, 
composed  of  four  testaceous  pieces,  moveable 
at  pleasure,  and  articulating  with  the  sides  of 
the  shell,  sometimes  near  the  base,  sometimes 
towards  the  middle.  The  union  of  these  valves 
forms  a  pointed  cone,  which  completely  covers 
the  opening  at  the  apex,  and  protects  the  mol- 
lusca,  who  can  open  it  at  pleasure  to  put  out 
their  arms,  and  draw  in  their  food.  The  increase 
in  the  height  of  these  shells  is  clearly  indicated 
on  their  lateral  valves,  whilst  at  the  base  are 
traces  of  extension  in  width ;  it  is  probable  that 
at  each  period  of  growth,  the  animal  disunites  its 
valves  and  connects  them  again,  having  added 
the  necessary  portion  to  their  size. 

The  Linnaean  name  of  Lepas  is  now  confined 
to  the  division  containing  the  Peduncled  shells.* 
The  mollusca  inhabiting  them  may  be  considered 
as  different  from  those  of  the  Balanus,  because 
the  tube  which  supports  the  shell  is  in  fact  a  part 
of  the  animal;  it  is  organized,  living,  and  fur- 
nished with  muscles  which  give  the  Lepas  the 
power  of  regulating  its  movements.  The  shell 
is  composed  of  five  valves,  two  on  each  side,  and 
one  long  and  narrow  on  the  dorsal  ridge  ;  these 
valves  are  united  by  a  membrane  ;  the  form  of 
the  shell  is  that  of  a  flattened  cone  ;  the  base  is 
sustained  by  a  tubular  flexible  peduncle,  attached 
to  marine  substances. 

*  Plate  X.  figure  7. 


LEPAS BARNACLE.  203 

LEPAS  Tintinnabulum* 
BELL-SHAPED  BARNACLE. 

Specific  character.  Shell  sessile,  the  valves 
irregularly  and  strongly  ribbed  longitudinally, 
and  the  interstices  delicately  striated  trans- 
versely ;  the  form  is  sometimes  conical,  some- 
times cylindrical ;  the  colour  is  pinkish  incli- 
ning to  purple ;  the  diameter,  which  is  some- 
times exceeded  by  the  height,  varies  from  half 
an  inch  to  two  inches. 

This  shell  is  found  in  the  West  Indies,  and 
coasts  of  Africa,  and  often  on  the  bottom  of 
ships  arriving  from  more  southern  attitudes; 
but  its  claim  to  be  considered  as  a  native  of 
Britain  is  very  doubtful. 

LEPAS  Anatifera. 
DUCK  BARNACLE. 

Specific  character.  Shell  compressed,  some- 
what triangular,  composed  of  five  valves ;  the 
two  lower  ones  are  large,  triangular,  and  faintly 
striated  ;  the  two  superior  valves  long  and  tape- 
ring downwards  to  an  obtuse  point,  the  upper  part 
angular  on  each  side,  the  top  rounded ;  these 
valves  are  also  slightly  striated ;  the  dorsel  valve 
is  long,  slender,  and  rounded ;  the  cartilages  that 
connect  the  valves  and  the  peduncle  are  usually 

*  Plate  X.  figure  6.          f  Plate  X.  figure  7 


204  MULTIVALVES. 

of  a  reddish  orange  colour ;  the  valves  are  blue- 
ish  white ;  the  length  is  about  an  inch  and  a  half, 
the  breadth  of  the  largest  part  is  an  inch  ;  the 
peduncle  is  sometimes  a  foot  long. 

This  species  is  found  in  all  parts  of  the  world, 
adhering  in  great  quantities  to  the  bottom  of 
ships.  It  attaches  itself  particularly  to  wood  : 
sometimes  pieces  of  timber  are  thrown  on  shore 
completely  covered  with  it.  A  most  strange 
idea,  formerly  prevailed,  that  the  Barnacle  goose 
was  produced  from  these  shells. 


QUESTIONS  ON  THE  MULTIVALVE 
SHELLS. 

1.  How  is  the  generic  character  of  Multivalve 
shells  determined  1 

2.  What  is    the    generic    character  of  the 
Pholas  ? 

3.  Why  is  the   Pholas  now  generally  con- 
sidered as  a  Bivalve  shell? 

4.  What  are  the  habits  of  the  Pholades  I 

5.  How  is  the  Pholas  supposed  to  perforate 
the  different  substances  it  inhabits  ? 

6.  What    is    the  generic    character  of   the 
Chiton  ? 

7.  Describe  the  habits  of  the  Chiton. 

8.  What  is  the  generic  character  of  the  Lepas  1 

9.  Describe  the  two  families  into  which  the 
Lepas  is  divided. 

10.  Describe  the  animal  which  inhabits  the 
Lepas. 


SHELLS  AND  THEIR  ANIMALS.         205 

USES  OF  SHELLS  AND  THEIR 
INHABITANTS. 

Testaceous  bodies  are  not  only  to  be  admired 
for  their  beauty,  but  valued  for  their  usefulness. 
Several  of  their  animals  afford  a  very  nutritious 
diet.  The  oyster  supplies  the  table  of  the  rich 
with  a  wholesome  delicacy  ;  in  many  maritime 
situations  the  poor  population  are  almost  entirely 
supported  by  various  shell  fish,  as  muscles, 
cockles,  pectens,  solens,  &c.  The  medicinal 
qualities  of  the  snail  have  rendered  it  a  suitable 
sustenance  for  the  invalid.  The  Mollusca  not 
only  contribute  to  supply  the  wants  of  man,  but 
form  the  subsistence  of  other  animals  ;  they  are 
the  prey  of  various  fish,  and  are  a  favourite  food 
of  seafowl,  who  exert  much  ingenuity  in  getting 
at  them  :  when  they  find  their  beaks  insufficient 
to  pierce  a  shell,  they  will  ascend  with  it  to  some 
neighbouring  eminence,  from  whence  they  drop 
it,  that  it  may  be  crushed  against  the  rocks.  The 
monkey  also  regales  himself  with  shellfish  ;  at 
the  reflux  of  the  tide,  when  the  Mollusca,  for 
want  of  water,  keep  their  shells  open,  he  stations 
himself  on  the  sea  shore ;  aware  of  the  danger 
of  inserting  his  paws  between  the  valves,  he 
drops  in  a  stone  or  two,  by  which  he  prevents 
their  closing,  and  is  enabled  to  extract  his  prey 
with  impunity.  The  shells  also  of  Testaceous 
animals  are  useful  in  various  ways.  In  America 

18 


206  SHELLS  AND  THEIR  ANIMALS. 

the  greatest  quantity  of  lime  used  for  agricultural 
and  architectural  purposes  is  made  of  calcined 
shells.  The  public  streets  of  Christianstadt  and 
Santa  Cruz  are  paved  with  the  Stromjjus  Gigas, 
and  the  town  of  Conchylion  is  entirely  built  of 
marine  shells. 

In  uncivilized  countries  the  natives  not  only 
delight  to  deck  their  persons  with  shells,  but 
where  the  working  of  iron  is  still  unknown,  they 
often  employ  shells  as  its  substitute,  and  convert 
them  into  agricultural  or  domestic  implements, 
and  also  warlike  instruments.  The  military 
horn  of  many  of  the  African  tribes  is  formed  of 
the  Murex  Tritonis.  The  blue  and  white  belts 
of  the  Indians  of  North  America,  used  as  sym- 
bols of  peace  and  amity,  in  opposition  to  the 
war  hatchet,  is  made  from  the  Venus  Mercena- 
ria ;  and  the  gorget  of  the  chieftain's  dress, 
is  constructed  of  the  Mytilus  Margaritiferus. 
Among  the  Friendly  Isles  the  permission  to  wear 
the  Cypraea  Aurantia  or  Orange  Cowry  marks 
the  highest  rank  of  the  country.  The  Cyprsea 
Moneta  or  Money  Cowry  is  the  current  money 
of  many  nations  of  India  and  Africa,  and  the 
liberty  of  a  man  is  often  bartered  for  a  certain 
weight  of  these  shells.  In  Grecian.  History  we 
read  that  the  suffrages  of  the  Athenians  were  on 
certain  occasions  marked  upon  a  shell.  Pearls, 
the  effect  of  disease  in  certain  Mollusca,  form  a 
portion  of  the  revenue  of  many  kingdoms,  and 
are  among  the  most  costly  ornaments  of  the 
noble  and  the  wealthy.  In  former  times  the  dye 


SHELLS  AND  THEIR  ANIMALS.  207 

extracted  from  the  Purpura  was  a  most  valuable 
article  of  commerce,  but  it  has  now  been  super- 
seded by  that  which  the  Cochineal  furnishes  in 
so  much  greater  abundance. 


A  List  of  the  Genera  of  Shells  as  arranged 
by  LinnsBus. 


MULTIVALVES. 

Singular.  Plural. 

Chiton.  Chitones. 

Lepas.  Lepades. 

Pholas.  Pholades. 


BIVALVES. 


Mya. 

Myae. 

Solen. 

Solenes. 

Tellina. 

Telltnae. 

Cardium. 

Cardia. 

Mactra. 

Mactrae. 

Donax. 

Donaces. 

Venus. 

Veneres. 

Spondylus. 
Chama. 

Spondyli. 
Chamae. 

Area. 

Arcae. 

Ostrea. 

Ostreae. 

Anomia. 

Anomiae. 

Mytilus. 

Mytili. 

Pinna. 

Pinn£8. 

UNIVALVES. 


Singular. 

Argonauta. 

Nautilus. 

Conus. 

Cypraea. 

Bulla. 

Voliita 

Buccinum. 

Strombus. 

Murex. 

Trochus 

Turbo. 

Helix. 

Nerita. 

Haliotis. 

Patella. 

Dentalium. 

Serpiila. 

Teredo. 


Plural. 
Argonautaa, 
Nautili. 
Coni. 
Cypraeas. 
Bullas. 
Voliitse. 
Buccina. 
Strombi. 
Murices. 
Trochi. 
Turbines. 
Helices. 
Nerltse. 
Haliotides. 
Patellee. 
Dentalia. 
Serpulas. 
Teredines. 


IS* 


EXPLANATION  OF  TERMS. 


Apex.  In  univalve  shells,  the  top  of  the  spire. 
Apices.  The  plural  of  apex.     In  bivalve  shells, 

the  points  over  the  hinge  :  called  also  the 

Beaks. 

Aperture.  The  entrance  or  opening  of  the  shell. 
Auriculae.  Small  earlike  appendages  placed  at 

the  sides  of  the  hinge  of  some  bivalve 

shells  :  the  diminutive  of  auris,  an  ear. 
Area,  or  Anterior  slope.  The  side  of  the  beaks 

where  the  ligament  is  situated. 
Areola,  or  Posterior  slope.  The  side  of  the  beaks 

opposite  to  that  where  the  ligament  is 

placed. 
Articulated.    Having  joints  ;  from  articul  us,  a 

joint. 
Annulated.  Marked  with  rings  ;  from  annul  us, 

a  ring. 

Alatce.  Winged  ;  from  ala,  a  wing. 
Adductor  Muscle.  The  muscle  that  closes  the 

valves  ;  from  adduco,  I  bring  together. 
Base.  In  univalve  shells,  the  extremity  opposite 

to  the  apex.     In  bivalve  shells  that  part 

of  the  margin  which  is  opposite  to  the 

beaks. 


EXPLANATION  OP  TERMS.  211 

Bivalve.     A  shell   with  two  valves  ;  from  bis, 

twice,  and  valve. 
Bifid.  Cleft  in  two  ;  from  bis,  twice,  and  fid  t, 

I  have  cleft. 
Bifurcated.  Having  a  fork  of  two  teeth ;  from 

bis,  twice,  and  furc  a,  a  fork. 
BranchicK.       Gills ;     from    the    Greek    foayxia 

(branchia)  the  gills  offish. 
Cardo  or  Hinge.    In  bivalves,  that  part  of  the 

circumference  where  the  valves  cohere. 
Carinate.  Furnished  with  a  keel-like  elevated 

ridge  ;  from  carina,  a  keel. 
Columella.  The  pillar  round  which  the  whorls 

form  their  spiral  circuit ;  from  colum  e//a, 

a  little  column. 
Convoluted.  Rolling  regularly  over  each  other  ; 

from  con,  together  ;  and  volut  ws,  rolled. 
Cephalopodes.  Having  feet  on  the  head  ;  from 

the  Greek  Ke<j>a\n   (cephale)  a  head,  and 

TroSes  (podes)  feet. 

Corneous.  Horny ;  from  cornu,  a  horn. 
Crenated.    Notched ;  from  cren  «,  the  notch  of 

an  arrow. 
Coriaceous.  Like  leather ;  from  cori  ww,  skin, 

leather. 
Callosity.  Hardness  of  skin  or  flesh ;  from  call 

us,  which  has  the  same  signification. 
Ciliated.  Furnished  with  a  fringe  like  eye-lashes; 

from  cila,  an  eye-lash. 
Cancellated.  Crossed  like  the  bars  of  a  latticed 

window  ;  from  cancelli,  lattice. 
Complicated.  Folded  together  ;  from  con,  with, 

together,  and  plica  re,  to  fold. 


212  EXPLANATION  OF 

Digitations  or  Claws.  Finger-like  lobes ;  from 
digit  us,  a  finger. 

Dextral.  Righthanded,  turning  round  the  pillar 
from  left  to  right,  the  usual  course  of  the 
wnorls  ;  from  dextra,  the  right  hand. 

Dorsal.  Belonging  to  the  back  ;  from  dors  um, 
the  back. 

Dentated.  Toothed ;  from  dens,  a  tooth. 

Diaphanous.  Capable  of  transmitting  light, 
transparent ;  from  the  Greek  5ia  (dia) 
through,  and  0<uvw  (phaino)  I  appear. 

Decorticated.  Having  the  bark  or  outer  skin 
taken  off;  from  de,  off,  and  cortex, 
bark. 

Dissepiment.  A  division  between  two  chambers 
in  a  shell ;  from  sep  es,  a  hedge,  and  dis, 
a  prefix  signifying  division. 

Decussated.  Crossed  like  an  X  ;  from  decussis, 
the  mark  X  (ten.) 

Disk.  The  convex  part  of  the  valves  between 
the  umbones  and  the  margin. 

Effuse.  Having  the  lips  separated  by  a  sinus  or 
gutter,  so  that  if  the  shell  were  filled  with 
water,  it  would  flow  out  at  the  sinus  be- 
fore it  reached  the  margin ;  from  fus  us, 
poured  out. 

Epidermis.  The  membranaceous  covering  of 
some  species  of  shells ;  from  the  Greek 
em  (epi)  upon,  and  deppa  (derma)  a  skin. 

Equivalve.  Having  equal  values  ;  from  equ  us, 
equal,  and  valve. 

Equilateral.  Having  both  sides  equal ;  from, 
equ  us,  equal,  and  latera,  sides. 


EXPLANATION  OF  TERMS.  213 

Emarginated.  Notched,   or  having  the  margin 

excavated  by  a  sinus. 
Ferruginous.  The  colour  of  rust  or  iron-mould ; 

from  ferrug  o,  iron  rust. 
Fusiform.    Shaped  like  a  spindle  ;  swollen  in  the 

middle,  and  tapering  to  each  end ;  from 

fusis,  a  spindle. 
Fluviatile.    Belonging  to  fresh  water  ;  from  flu- 

vi  us,  a  river. 
Genus.  A  separate  family,  distinguished  from  all 

others    by    certain    permanent    marks, 

called  generic  characters ;  from  gen  us,  a 

kind. 
Gaping.  The  valves  so  partially  closing,  that 

the  margins  do  not  touch  at  every  part  of 

the  circumference. 
Imbricated.    Lying  one  over  another  like  the 

tiles  of  a  house  ;  from  imbrex,  a  tile. 
Iridescent.  Displaying  the  varied  colours  of  the 

rainbow ;  from  irides  cere,  to  shine  like  a 

rainbow,  in  Latin  iris. 
Ineqivalve.     Having  unequal  valves;  from  in, 

not,  equ  us,  equal,  and  valve. 
Inequilateral.  Having  sides  not  uniform ;  from 

in,  not,  equ  us,  equal,  and  latera,  sides. 
Involuted.     Rolled  inwards  ;    from  involut  ws, 

rolled  up  in. 
Laminated.    Having  thin  layers  or  scales  called 

laminae. 
Linear.    Extremely  narrow  in  proportion  to  its 

breadth,  and  of  nearly  equal  diameter 

throughout. 
Length.   In  Bivalves,  the  dimension  extending 


214  EXPLANATION  OF  TERMS. 

from  the  hinge  to  the  opposite  margin ;  in 
Univalves,  that  from  the  apex  to  the  base. 

Ligament.  A  cartilage  which  connects  the 
valves  ;  from  lig  are,  to  bind. 

Lanceolate.  Shaped  like  the  head  of  a  lance. 

Lips.  The  margins  of  the  mouth  of  a  univalve 
shell.  The  columellar  lip  is  the  margin 
nearest  the  columella.  The  outer  lip  is 
the  outer  margin  of  the  aperture. 

Locomotion.  The  power  of  moving  voluntarily 
from  place  to  place  ;  from  loc  us,  place, 
and  motion. 

Multivalve.  Having  several  valves,  from  mult  us, 
many. 

Mollusca.  The  animals  inhabiting  shells  ;  the 
name  is  derived  from  mollis,  soft.  They 
are  divided  into  two  classes :  those  which 
have  a  head  called  Mollusca  cephala, 
from  the  Greek  «f0aX>?  (cephale)  a  head; 
and  those  without  a  head  Mollusca  ace- 
phala,  from  the  Greek  a  (a)  without,  and 

K£<pa\ij. 

Muricated.  Having  little  pointed  knobs;  from 
murex,  the  sharp  point  of  a  rock. 

Marine.  Belonging  to  the  sea  ;  from  mare,  the 
sea. 

Multilocular.  Having  several  chambers,  from 
mult  us,  many,  and  locul  urn,  a  little 
chamber. 

Operculum  or  Lid.  A  plate  or  door,  with  which 
some  species  close  the  aperture  of  their 
shells,  from  oper  ior,  I  cover. 

Orbicular.     Quite  round,  or  circular 


EXPLANATION  OF  TERMS.  215 

Peduncle.  The  tubular  support  of  some  of  the 
Lepades. 

Pellucid.  So  clear  that  the  light  is  seen  through ; 
from  per,  through,  and  lux,  light. 

Plicated.     Folded  or  plaited ;  from  plica,  a  fold. 

Punctured.  Pricked  or  marked  with  small  dots ; 
from  punct  um,  a  point  or  dot. 

Patulous.  Lying  open  or  spreading ;  from  pat  ere, 
to  lie  open. 

Quincunx.  Disposed  alternately  as  in  rows  of 
spots,  when  the  spots  of  each  row  are 
opposite  to  the  space  between  two  spots 
of  the  next  row ;  from  quin  que  five,  and 
unx,  ounce,  as  the  weight  representing 
five  ounces  was  stamped  thus  :•: 

Rotatory.     Like  a  wheel ;  from  rota,  a  wheel. 

Rostrated.  Having  a  beak,  from  rostrum,  a  beak. 

Retuse.  Having  the  lower  whorls  of  the  spire 
pressed  into  the  body  whorl,  from  re, 
back,  and  tus  us,  beaten. 

Reversed.  Applied  to  spiral  shells,  whose  volu- 
tions turn  in  the  contrary  direction  to  the 
generality  of  shells,  and  which  are  also 
called  sinistral,  or  left  handed,  from 
sinistra,  the  left  hand.  If  when  a  shell 
is  placed  on  its  base,  with  the  front 
facing  the  person  looking  at  it,  the 
aperture  is  on  the  right  side  of  the  pil- 
lar, the  shell  is  said  to  be  regular  or 
dextral,  if  the  aperture  is  on  the  left 
side  of  the  pillar,  it  is  said  to  be  reversed 
or  sinistral. 


216  EXPLANATION  OF  TERMS. 

Rugose.  Rough  or  wrinkled ;  from  rug  a,  a 
wrinkle. 

Retractile.  Capable  of  being  drawn  back ;  from 
re,  back,  and  tract  us,  drawn. 

Reticulated.  Crossed  like  net  work ;  from  re- 
ticul  um,  a  small  net. 

Revolute.  Rolled  back;  from  re,  back;  and 
volut  us,  rolled. 

Spire.  The  upper  whorls  collectively;  from  the 
Greek  °™p  (speir)  convolutions  gradu- 
ally increasing  in  diameter. 

Suture.  The  circular  line  of  the  spire,  where 
one  volution  meets  another ;  from  sutur  a, 
a  seam. 

Species.  The  subdivision  of  a  genus,  and  dis- 
tinguished from  all  others  of  the  genus  by 
permanent  marks  called  specific  charac- 
ters. 

Striated.  Marked  with  fine  striae,  or  lines, 
either  hollow  or  raised ;  from  stria,  a  stripe. 

Sinus.  A  gutter,  or  curvature  ;  from  sin  us,  a 
curved  line. 

Subulate.  Tapering,  or  pointed;  from  subul  cr,  a 
pointed  tool. 

Sides.  The  right  side  of  a  univalve  is  that 
opposite  the  right  hand  of  the  person 
looking  at  it,  when  the  shell  is  placed 
on  its  base  with  the  aperture  in  front : 
the  left  side  is  that  opposite  the  left 
hand,  the  shell  being  in  the  same  position. 

Terrestrial.  Belonging  to  the  earth ;  from  terra, 
earth. 


EXPLANATION  OF  TERMS.  217 

Testaceous.  Composed  of  the  materials  which 
form  shells;  from  the  Latin  testa,  a 
shell. 

Tentacula.  The  feelers  of  the  mollusca ;  from 
the  Latin  tent  o,  I  try. 

Turbinate.  The  body  swelling,  and  spire  com- 
paratively small ;  from  the  Latin  turbin  is, 
of  a  whirlwind. 

Turreted.  The  whorls  gradually  decreasing  to 
a  fine  point ;  the  length  of  turreted  shells 
greatly  exceeds  their  breadth. 

Teeth.  The  pointed  protuberances  at  the  hinge 
of  Bivalve  shells  ;  the  cardinal  or  central 
teeth  are  those  situated  on  the  hinge ;  the 
lateral  teeth  are  those  at  the  sides  of  the 
hinge,  and  are  often  remote. 

Tuberculated.  Covered  with  tubercles,  or  small 
protuberances. 

Tortuous.  Twisted;  from  the  Latin  tort  us, 
twisted. 

Umboncs,  or  Bosses.  The  swelling  part  of  bivalve 
shells  near  the  beaks ;  from  umbo,  the 
boss  of  a  shield.  The  highest  points  of 
these  are  considered  the  summits. 

Umbilicus.  A  small  hollow  at  the  base  of  the 
columella,  visible  underneath. 

Undulating.  Wave-like;  from  undula,  a  little 
wave. 

Univalve.  A  shell  composed  of  one  valve;  from 
un  us,  one,  and  valve. 

Volutions,  or  Whorls.  The  distinct  turns  of  the 
spire. 

19 


218  EXPLANATION  OF  TERMS. 

Varices.  Longitudinal  gibbous  sutures  formed 
in  the  growth  of  the  shell  at  certain 
distances  on  the  whorl;  from  varix,  a 
swollen  vein. 

Vermiform.  Resembling  a  worm ;  from  the  Latin 
verm  es,  a  worm,  and  forma,  a  form. 


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